Not sure if I posted this here or another thread but have a read and then see if you wan to take it easy still, best way to glaze the bores and kill the rings is to take it easy in my opinion
http://www.mototuneusa.com/break_in_secrets.htm
Have run in plenty of engines by loading them up first run and never had any dramas
If the shop has a dyno maybe they can run it in on the dyno for you before you pick up the car