First off, Great garage. Congrats on the design.
As for the StrongHolds, I have to agree with you on their strength and durability. We use them at work in an industrial environment and they seem to stand up to everything. We use them sometimes to hold 800lbs of parts fixtures on one shelf. Not uncommon to see 16 piston/con rod assys stored in one cabinet (at 80 lbs each).
Couple of questions for you... What kind of anvil do you have? What weight?