I personally found the lower bolts harder to access and remove than the upper bolts. But your experience may differ from mine. If you hadn't already seen my thread on the rear brakes, check it out here:
my-not-so-fun-rear-brake-job-t604439.html
If you can get the tech to crack the bolts loose, I think you'll be ahead of the game; especially if the hardware is corroded. And it'll also help if you are planning to change out the rotors, as I think the caliper bolts are torqued to around 80 ft-lbs; just about what the lug nuts are tightened to. If/when you do end up working on your brakes, please let us know how it works out for you.