I have the skid shoes on my loader mounted Meyers ST90 set pretty high right now (I haven't measured, but it's probably 1.5" lower than the blade edge) and I have very little problem with digging in, except where the gravel is exceptionally soft and beside the road, where I have to plow at an angle. In these cases I just angle the cutting edge up a bit more. Our driveway is not even or level at all, but I can still plow in 10th gear except when the snow is extra deep or heavy. We had 10" of heavy snow on Wednesday, I had to drop down to 9th gear for that.
Does your blade have a chain going back to the loader so it floats?