BTW, I used a stack of wood pieces to hold the caliper when I took it off and the caliper was well supported. I also measured the disk for thickness old vs new and after 25k km, there was no wear on it hardly so I had no issue with the piston and the pads sliding back on there.
Go figure, that is how much rear braking happens on these cars even with a Wildwood valve being used. I know most of my driving is on the highway, so we can conclude that the front is where all the action is for sure.