If the gantry racks then it is that small a movement I don't care. I disconnected one side and tried to push it, I could feel no movement but I did not use a dial indicator.
The AM882's have tripped on stall but only when I've tried to get too much speed/acceleration from the machine, when tuned to sensible values they do not trip.
I don't know if they tripped due to racking or something else.
I am still using only one homing switch on the X axis and that is working fine for me, your machine (silyavski) will be stiffer then mine I imagine so it should work for you too.
If anyone has doubts they should probably use one motor and connect the two ball screws with belts.