I may be late as you may have poured the concrete, but I made floor pockets out of 4" galvinized rigid pipe couplings. I welded a 1/4" plate to both ends, had a buddy machine chain hook cross tee's in the top plate to accept 3/8" chain. Then welded 2 pieces of 12" long rebar to the sides. The pockets are flush and always available, just drop a chain in and go. I set (5) of them in a diamond pattern 5' apart from eachother that way I can straighten metal by chaining the ends while jacking the middle.
Also, don't forget the I install 20' of #6 bare solid copper wire in the concrete footer for your electric ground. Leave about 6' additional feet sticking out at your PVC conduit for the electrician to connect to the sub-panel.
Mike B
