Haha... Interesting developments I am not sure what were the small inconsistencies with the original TDC 2.0 setup but I would boil it down to some accidental micro installation error with either seating the bucking, maybe some dust got inside, maybe a small debris got in between the nub and bucking, etc. Normally our tolerances are dialed in pretty well where the nubs slide in and out with small force applied but have 0 wobble but sometimes there might be a lemon or two now that we are doing production runs in hundreds. If that's the case, we are always happy to send some free spare parts to help debug the issue and see if there it was a lemon.
I strongly believe and from my personal testing this has been true - as long as the (1) the nub is somewhat not moving around excessively and (2) covers the shape of the bucking evenly and large enough area - the performance comes purely from TDC screw and having the ability to really fine tune it. I obviously won't go around announcing that nub / arm contact surface shape doesn't matter but I could not tell any difference between our different nubs we've made for TDC 2.0. We made them available so everyone can do the testing and hopefully someone does an actual semi-scientific research if that really does anything at all to the accuracy / overall performance of an airsoft rifle. But until that happens, more power to the user so every one can come to their own conclusions and see what feels good to them.
The system with the hybrid design you've come up looks overly complicated to me but hey, if it works, it ain't stupid! Props to you and rock on.