Rear trailing arms and upright geometry?

Been a long time now since i last posted here.
I'm trying to get the rear suspension together on paper before i manufacture it.

What i can't figure out is how to handle the type of suspension.
Should i see the trailingarms as an extension of the wishbones and thereby make them equal length and horisontal when in rideheight?

OR should the trailingarms be seen as a true 4link system and be used for antisquat?
Using it for antisquat would mean alot of "unnatural" movement for the upright and wishbones and would likely require rosejoints at all positions to allow the extra rotational movement without ceasing.

Thoughts and ideas?
I need to wrap my head around this.

Btw. Saw GT Fortes rear suspension simulation on the tube, and he doesnt seem to use any antisquat, since the upright neatly moves straight up/down and doesnt twist while moving. Right or wrong?