Mark- taking the second level discussion a bit further. Typical house floor framing is16" on center with 3/4" subfloor. A few strategically placed columns should do the job and you could lower the whole thing. My second level is nothing more than 1/4" luan and 1" dowels. Holds even heavy post war engines just fine.
Happy to help on the cassette. I like the whole system and would consider it myself if I had more room.
Bob