Got a set this week myself. They are good in my opinion. I have 2 under the back legs of DaC, the machine doesnt move, and does not effect nudging. I simply lift the front of the pin to move it around.
Great idea Greg!! since i havent recieved mine yet 
does it effect the angle too much ( too steep) having the wheels on the back?
you gotta allow for the extra angle it will put on yes, take this into account if you intend to leave them on
