Getting the best out of standard suspension components for touring driving today

Following some discussion on XK torsion bars:

I’m curious how much the E-type torsion bar works in torsion and how much in bending, compared with the XK bar which is pure torsion around its axis. I think I’ve worked out how to estimate and combine the two effects, would appreciate a figure for the working length of an E-type bar (S1 or S2). Within 5mm accuracy would be fine.

I have a feeling I’ve already asked that or a similar question somewhere, apologies I can’t find the detail and thanks for any information.