By the way I perfected my costar stab integration with a 3d printed plate, without any modifications, after printing, I only graze the top/left/right side of the cutouts, leaving the bottom part as it is, my latest prototype had the best spacebar I've used, hope I can be this lucky with my final plates :)
Apart from the stabilisers, I think getting the plate closer to 1.6mm improves the switch rigidity, at 1.5mm the switch is able to wiggle a bit, I don't know after what point the switches will be unable to latch on, however I will probably try 1.6mm next
Overall there is an incredible grip with all components, once soldered, I think switches will require in-place destruction to be removed/replaced - which is what I want - hate wiggling/crooked/displaced switches/keycaps