but I don't know about the flatties though.. frame is build for world cup racing
my suggesting is not going for a fork with longer ac then 410mm.. better then a stem or handlebar with some rise
obsys fork, yeah.. that's a project of its own.. and seals are starting to get very rare as i've understood.. put up a wanted thread on sunnproteam.biz that's my suggestion.. i've never taken apart an obsys and have never changed seals, so can't sadly help on that apartment.. i've owned 4 carbons, 2 that leaked, 2 that didn't, of of those 4 i have today one of each.. one on my exact ti the best.. still going strong after years of riding.. only maintenance is inflating some air once a month *thumbs up*
soft tail rear flex need no maintenance at all.. system use a 30mm elastomer which u easily change when gone hard - every 3-5 years :p
I have a swap thread on sunnproteam.biz for a frame like yours, giving up my exact ti flex... so if u ever
I have the road tyres on as this is my only bike so I have it set up for the type of riding I do, mainly on country roads and such. Being honest, the bike has had a very easy life with me, thats why its in such good condition and original. I wasn't too keen on the low,drawn out position it has with the obsys forks though, so I opted for a steel rigid fork. It has an A-C of 420mm so will see how that goes.
It's a pity about the obsys forks though, I might try your suggestion about the sunnproteam forum for the seals. It amazes me though, are they that different that no other seals will do???