I have read your posts about the reverse issues, and i think the answer is no.
The ZK tracks pretty true forward and reverse. While there is always a need to tweak side to side to keep going in a straight line, due to ground undulation and a little play in the controls, there is definitely equal power to both wheels in both directions.
The ZK uses a series of ball joints and levers where Toro is using cables. Wright used to use cables. I feel both systems have benefits and draw backs. As all those ball joints wear in, it adds up to a bit of slop in the controls (after over 500 hours). But then again, I feel it is holding up pretty well given the number of moving/wearing parts in the linkage system.