8x4x30 is the external dimension right? the volume the tank can hold should be base on the internal dimension, maybe that's why it's 535 instead of 600??
Burner, you are wasting the tank, for the tank sack please bring it to my house. I'll supply you with beer and pizza at the finish line. lol
Stocking of the tank should be easy, just put everything you ever wanted but couldn't due to lack of tank space in that tank. even it's 100000 neons.
building the stand should be easy, you want a material list? I think I have mine saved in an excel file when I designed my yet to be build plywood tank. I can email to you if you want, just double check it to make sure it's everything you need.
second thought, the list might not be good cuz the stand I designed isn't very tall so you can't fit anything under it (30" total height with only 20" clearance since I plan to have filter behind the tank and stand).
is the tank drilled? check out Li's thread on his 600g setup, I think he's using sand filter for pool. a lot of people use those filter for large tanks. or you can use one of you tank you plan on selling as a sump if you don't want to spend money on new filter, just get a return pump that's powerful enough for the turn over rate you need.