Home now, and measured with a compass as I don't have tools to take out the whole headset myself. Looks like I can actually maybe get 33mm, maybe a little more after re-facing. Really quite surprised, seems like lower part of the headset that's in there - I measured bottom of crown to bottom of headtube - is pretty large which is making the fork come out short up top (and which made me worry!).
- So any ideas of a period headset that I could hunt for that might fit?
Velobase has the '50s Gran Sport at 33.8, it would be perfect but bet it'd cost even more than a new steerer would have!!!
- and can you use something a little taller and get away with it?
Thanks for all the help, really is much appreciated, just wish I had the knowledge to be able to reciprocate more often. Maybe with time...!