I just finished replacing the belt on my V6's compressor, tonight. (Note that all I loosened was the bottom bolt. Nothing up top.)
Moving the compressor towards the engine in order to slip the new belt on proved to be not so much trouble.
Getting the compressor to move back out, to take up the slack in the belt, proved to be a whole 'nother story.
Prying against the lug on the compressor, through the holes in the bracket, didn't do much but flex the bracket downward. Couldn't get enough leverage or "purchase" to move the compressor back.
My solution was to fix a small-ish C-clamp to the back edge of the bracket, under the compressor, as close as I could get to the engine block, without the cradle getting in the way.
Once that's tightened, it will provide a flat surface (as opposed to a slanted edge) to pry against, to push the compressor back into place.
Once it's "close", prying against the lug, through the holes, will work.