Well, it was interesting.
Mark tested my flexibility with a few static stretch type movements - he gave me 7/10! We talked about what I wanted to achieve, and how different frames are set up to do different things.
Then he stuck velcro tabs on my shoes, knee, hip, shoulder and arm, and attached something that reminded me of Christmas tree lights. This meant that the Retul sensor could see me moving (and my legs going around) in real time, and we could start moving things about while getting feedback from the measuring system.
We moved the saddle a bit forward (this seemed to be a bit like a scientific KOPS - I was expecting it to go backward from what I'm used to), and up a bit until it was comfortable and the angles (foot/ankle and knee) were good. Then we moved the front end of the bike up and down and in and out. The system was able to give a back angle number, and I could feel how the different angles worked. We ended up with a good comfortable setup with an angle of 46degrees - then Mark measured the jig to give me a stack and reach measurement. We then checked out some bikes (eg Spec Roubaix fits approx in a 58) and tried it again, with a shorter reach to see if it worked a bit better. The final stack/reach numbers were 600 and 400 respectively.
Finally, I got my bike and saw just how far out it was - the saddle needed to go up about 6cm and forward about 3! The stack height is rediculously low, so with the saddle correct, riding on the hoods felt like riding a stretched out super low bike, even with a tall stem at it's maximum! So it's time to get something comfortable - will probably be "endurance" or "gravel" style bike with stack/reach numbers that suit me. Mark is going to email me a report with tour conclusions and some suitable bikes.
It was a really good experience, and a really interesting setup. Very pleased I did it - I can now go ahead and get a comfy bike without feeling guilty about getting rid of an old bike that has sort of become part of me!
Cheers
Duncan