Foam is in, and by my calculations, it's going to support about 1.3lbs/sq in. Somehow, I thought it would be more. This 3/4" foam barely compressed, and the tank remained perfectly level. Very happy right now. I've got it about 3/4 full, and I'll let that sit over night. I'll drain it later this week as I move closer to finishing it.
So far, the hardest part was putting the tank on the stand alone. I should have waited for help, but I couldn't wait. I'm sure I'll feel it tomorrow.