Thanks guys! The help and encouragement I received from the BFM community really got me through this. These tops took a lot longer to complete than I thought they would. Good thing I wasn't working against a deadline.
And please; go ahead and steal/reuse/remold what few original ideas I managed to think of! If I owed a dollar for every idea I've swiped from you guys, I'd owe Bruce about $14 and the rest of you a few bucks apiece. LOL! It's all good, my friends.
The mounting platforms have been done before, but most folks use the external tophats; I think using normal, internal hats looks a lot cleaner, but it is more work to build the platforms my way. Personal preference. The key to the mounting platforms is using 3/4" material (good ply, not OSB/particle board/MDF crap...I used Oak ply), doubling it up where the tophats mount and brace the crap out of the box. It really is just a "sealed cargo skid" with tophats in it. Also, getting the tophats aligned with the cabs' center of gravity is of the utmost importance. I found the COG on one cab and went with that measurement. Which is why my COG is not perfect; stacking that second cab changes the COG...I didn't know that while building. I got it close though. I'd say if my hats were about 1/2"-3/4" more forward, it would be perfect. That said though, a lot of times, the "floor" on which the tripods sit is not perfect. My backyard being the perfect example. In that case, you have move the tripods this way and that way to get eveyrthing to sit level anyway, so I guess a PERFECT COG is not mandatory. You have to get as close as possible though, b/c that's what centers all that weight, directly above the stands, pressing straight down, instead of coming down at an angle. Hope that makes sense. Too bad I'm a complete idiot at math; I think I'd have made a decent engineer.
OH, and the recesses on the platform for the cab's feet is mandatory. The feet "lock into" the holes on the platform and the cabs are solidly located atop the platforms, preventing any side to side or back to front motion. Strap the whole thing down and you would have to literally knock the stands over to get the stack to come down. Not planning on testing that anytime soon, but you get the idea.
If I knew all my DJ gigs would always be indoors, I'd build some collapsible wooden platforms...sorta triangular in design...think "Oil rig tower" and you'd be close. But something like that would absolutely need to always be on a concrete/wood floor. With my fledgling business, I'll be playing a lot of "Barney's Happiest Sing-Along Songs" (kill me now...) at backyard kiddie parties, so I need the flexibility that tripod stands offer. It is a quick setup though. Most time-consuming part is the straps. I'd say opening up four stands, throwing the platforms on, stacking the cabs and strapping them down took me 20 mins yesterday and I was in no hurry. When it comes to safety (and getting sued) I don't cut corners.
For anyone curious, I bought the black cargo straps from here. They ship quick too. Six bucks each; you cannot go wrong.
http://www.uscargocontrol.com/Ratchet-S ... ted-S-Hook