To make you understand why I'm having difficulties with implementing crawling... CCT doesn't change it's hull like usual entities in Acknex do, first of all I need to unregister and register CCT back in physX everytime I change it's size (when I go crawling and back to standing, with physX 3.x you don't need to do this, but native Acknex physX is only 2.x), plus when I lower 'max_z' to decrease the size of the bbox, CCT instead of lowering the upper 'max_z' only, makes the whole hull smaller, take a look at this screens:
So the thing is, that I need to update the Z position of the CCT shape, but it's different to the one we see in the Acknex (model's position with it's bbox size). I found out that with the CCT setting that I have in my demo, I need to lower bbox model with 10.8 quants when I go to crawling (so it actually looks like only the upper side of the bbox goes down). In 3dgs_snakes plugin there was that nice function called 'pX3ent_getfootposition' which used to return the foot position of the CCT hull (independent to it's size, cause foot position did not change!), native Acknex physX misses such useful function... (maybe cause it's outdated, and 2.x SDK did not support things like this? hard to believe, but it might be the answer). Even after changing the Z position manually 'by hand', I found out that it ruined the whole gravity movement that I have... CCT just falls through the ground after going to crawling state and then back to standing. So currently I'm having some difficulties with all this crap (this is why I hate Acknex native physX! it's too outdated and not flexable, and I don't really want to mention all the bugs it has). Anyway I'll try to sort things out and handle this situation, then I'll realise updated version with crawling and some tweaks.

Best regards!