Hi Mark,
The reason i mentioned the rec. tube chassis is that they can be bought in any stage, for example i had ART build my Anglia chassis, and it cost me $1050.00 fully welded with mounts for the strut front end and a 4 link.
I didn't know that you already had a mock up for a tube chassis.
By the way you got a good body to start with. I would go to the expense of ordering the SFI specs. either 25.2 or 25.4 for $35.00 that way you won't have any surprises when you go to have the car teched, i think it has to be a double lower tube chassis to certify to 25.2, single tube for 25.4, i do know that my rec, tube chassis will not certify lower than 7.50, but i don't think i want to go faster than that in a 92" wheelbase car anyway. I do have a Miller tig, so i'll be useing cromoly for the cage. good luck and i hope the kids really enjoy the build.
Keep us up to date on how it's going, and i think theres a lot of people on here that has most of the answers to your questions, which i donot have for sure.
Zip.
Here's the web page for the specs.
http://www.sfifoundation.com/