a few stupid questions

I have a couple of stupid questions for you guys.
Im currently working on my hawk trakatak - yes i know, i should get a better bike bla bla bla (im still building my RSP) but im emotionally attached to the bike, i dont know what it is, i just love the thing. so far i have got new tyres and tubes and cables all round and fitted them (just adjusting gears now). Im thinking about a few "upgrades" just to make the bike just that little bit better.
Im thinking about going from 18 speed to 21 speed, i know i will need to change the shifters, the rear mech and ofcourse go 7 speed on the rear wheel (im due new wheels in the next 400 miles anyway) but to fit a 7 speed rear where a 6 speed usually goes, will i need to bend the frame to fit the wheel in? if i do bend the frame what would the consequences be?
V-brakes - the bike currently has cantis on and im thinking about going to v-brakes, i already have the levers and callipers ready but, with the rear being specific plus having the cable stop? just before where the hanger goes, how would i route the cable? just cable tie it to the frame and hope for the best or would i come into some issues? is there a adaptor that would allow me to overcome any issues if any?
also, im going to fit some bullhorn bars just so i have a few more positions on the bike for longer rides, which do you think is better? bar tape or grips? i can get grips for a decent price - roughly the same as bar tape would be, but which do you guys think is better?
any help/advice appreciated, thanks.

Regarding the rear wheel-width issue.

I guess the 6 speed is 130OLN (over lock nut) width. The distance accross the 2 outer lock nuts on the axle. Modern stuff (7speed onwards) is 135OLN.
You can 'cold set' the rear end of a steel frame, gently easing each side open by the same amount. The final aim is to obviously fit in the new wheel, but to avoid the dropouts being at an angle accross the hub locknuts. The rear drop outs are one of the most stressed points on a bike frame, if the area is subject to excess stress when the wheel QR or bolts clamp down on the area the dropout/frame join could fail.

Re:

Hi, nice to see you are looking after a bike you really like.

V brakes.....so you have them and why not fit them, they do bite better than cantis, the cheaper ones anyway.

The front brake will be direct to the noodle anyway. As for the rear, run the outer cable from the lever adjuster barrel to the rear noodle, one direct run. Use some cable ties to fix it tidy.

Apart from that, my opinion is to keep it as it is, drivetrain wise. The extra 3 speed will make little difference unless you are going ape on the moors and feel you need the gears.

Personally i don't use riser bars or bull horn style. So i would use flat bars with comfy grips, the ergonomic style with the bilge to support the palm of your hand.

get some pics up.

this is the latest picture I have of it, just before I redid the cables and properly got the wheels on today (they were loose in this pic).
im going to be using the bike pretty much everyday, for commuting, taking my little sister around the park, fun rides on the weekends but nothing like hitting Cannock chase lol.
I want to change the handlebars purely because if I stay in one position for more than 15-20 mins my back starts to ache and having recently ridden a bike with bullhorns I found that being able to change my position regularly over a 60 mile distance was quite nice. ive had bullhorns before but im getting back into cycling seriously now after some health issues and im covering quite a bit of distance regularly. the bike I rode with bullhorns had grips and not bar tape on so I think ill get a set from LBS if they have any.

im umming and arring about the 7 speed rear change, it might be worth it, it might not, the bike will need new wheels in 400 miles anyway so if im going to get new wheels the opportunity is there to convert and get new derraileurs etc while im there but bending frame etc and just risking more stress on a certain area - im not keen on.

Re:

Get some bar ends instead. Cheap as chips and offer a minimum of a second riding position (depending on what type you get) to ease the pressure. I could send you some stubbies for the cost of postage or some longer ones for a couple of quid more.

thanks for the offer, ive got some on a scrap bike at the top of the garden im sure, ill put them on tomorrow and see if I like them, if not ill just put the bullhorns on.

this is already kind of turning into a project -
I was messing around with the brakes trying to set them up so I didn't have to replace with v-brakes, the rears work OK now. the fronts just weren't playing ball, so off upto the top of the garden I went, found a bike with v-brakes. took the front set off which happen to have good pads and a cable, installed them onto the hawk, 5 mins of messing (mostly drinking my cuppa) and they were on and adjusted properly. v-brakes are so simple, I just love them. do need to change the outer cable but for now, theyre working and that's what matters.

No harm or problem on it not being a yeti or anything. I think 3/4 of the battle is getting something that fits and is comfortable no matter the distance
And sure, building up in period kit is desirable though not set in stone and tbh why not fit a few bits it wouldnt have had on originally if it makes the ride more comfortable or sheds weight, and shedding weight is a must for this

one of the major things for me is getting the right fit, im 6 ft 7 so i need to have a frame that fits nicely and be able to adjust it to how i want it. every other bike ive tried, ive never managed to get the fit right apart from on this and the short period where i had my RSP built up. im not bothered about weight etc as i ride with panniers on the rear 99% of the time, cant really remember the last time i rode without panniers and i dont bother going anywhere too fast. the biggest things i focus on are comfort, handling and stopping. this bike does it well enough for me.
i tried out the bar ends and just didnt like them so im going with bullhorns, that will be tommorrows job.
pic of front v-brakes
also considering removing the rear mudguard + pannier rack + painting them + a front mudguard i have and then going both front and rear black mudguards with black pannier racks.

Just been out on a short 5 mile ride before I change the bars. Have to say im not very impressed with the tyres but for the price £11.3? per tyre? I suppose for now they'll do and when replaced can be used as a spare set. ill stay away from schwalbe city jet tyres from now on. other than that. loved it. gear changes are so smooth with new cables now and the brakes - its so nice to have working brakes :facepalm: