Mixing old and new, old TA / Stronglight compact with modern

And there I was worrying if you had sold the Norman Fay!

Thanks, I'll see what M737 with a short BB feels like.

Kermitgreenkona has the Norman, it will end up with me again soon, I'm sure.

So would a TA/ Stronglight be a lot more flexy than an hollow tech?

A lot of this is Shimano marketing puff, as there is no energy loss in the crank from flexing - it simply springs back. The deflections are relatively small anyway, cartianly by comparison with bottom bracket flex.

When the bike industry went to aluminium frames (because they were cheaper to make than steel) then they were noticeably stiffer and harsher to ride. 'Not harsh sir, stiff! Low energy loss!' And thus the myth was born. As Cycle journalism generally doesn't dare moon the Shimano gorilla, this stuff doesn't get challenged. For some reason the magazine that did real-life tests on a jig and worked out that the latest Dura Ace shifted more slowly than the old one didn't get many more reviews to do. Etc.
If you read the Bicycling Science book, US Army research suggests that harsh frames would be actually less efficient as they bounce the muscles around which DOES give an energy loss.

All you can be sure of is that you won't notice whether it is or isnt, and any difference in speed will be microscopic

It will weigh a few grammes more if that matters

I think what attracts me to going back to square taper is that in 7 years, I've had 3 hollowtech bottom brackets and 2 pairs of cranks. I don't remember ever having to change them so much beforehand?