Tie a rope to the ramps and put the other end of the rope under your back tires, it doesn't take much to stop them from sliding, I used about 3/16 diameter rope.
CDI makes a quality torque wrench, I'm pretty sure they make them for Snap-On, I have one of each and they are identical and the CDI cost less than half of the Snap-On. They also come with a calibration sheet.
I installed my XPR-10A with the power unit on the left side like this one, I had to add a couple small clamps to hold the cable closer to the column because when the lift got near the top of the travel the carriage would contact the cables and stop the safety latches from engaging.
I just went through this yesterday, you can see where the tabs are welded looking on the outside of the carriage, my arm fit through the opening on top and I was able to just drop the cable into place.