<font color="blue"> Everything I've read,...</font>
My JD8A Backhoe is a subframe mount. The Operator's Manual pictures stabilizers, loader bucket and all 4 wheels on the ground when in "digging position", but also says "To help prevent damage to backhoe: Raise tractor only with stabilizers." I think that's a warning not to raise it with the BH bucket, but doesn't say so, in so many words. So, instructions are not real clear. At least raising the tractor with the stabilizers seems to be acceptable from reading the Operator's Manual.
<font color="blue">... and everyone I know with experience says to keep the rear tires touching the ground </font>
Unfortunately, I don't know anybody with any kind of Backhoe experience, but the construction BH operators frequently have their tractor tires of the ground while working. My personal experience is that my BH moves my tractor around no matter what I do, but the tractor stays put best with loader bucket rolled forward so cutting edge is vertical, firmly on the ground. Usually that means front tires are in the air. And rear tires are off the ground, too. The stabilizer pads hold the ground better with all the tractor weight on them.
Now, both my loader and BH stabilizer arms will drift over a few minutes, so wheels find their way back to earth. If I notice I'm losing grip on the ground, I just bump the wheels back into the air.
OkieG