I’m the same height/build as you and have a 20″ 456Ti (had a steel one before).

Played with many bits and pieces but have settled on a 140mm Thor fork, 711mm Easton DH carbon bar and an On One 60mm stem.

It rides great and still gives me plenty of breathing space; not managed a 100 miler , but done plenty of 40/50/60’s.

Is it the image or are the bars on the 456 set so they droop at the ends? I think they should be more back & upsweep than droopsweep, its not your true problem but will lift the bars a bit..

How did the 100 go?

It is very low at the front, yes the frame can take 100 forks as the name suggests, but even from those images its clearly a lot lower at the front than your old bike. IE the relationship of saddle to bar height rather than height off the floor.

Well, I got my 80mm stem and did my “test ride” at the Kielder 100 last weekend. It was so much better! Spot-on, in fact. I got a 25 degree one so it is quite high, I will play around with dropping it down on the spacers. But anyway, thanks for the advice. I never would have thought 20mm could make so much difference!

result!