I'm building up my Demon to be an Open Track/ Autocross/ Optima car. I have quite a few spare parts lying around and could use some advice on what would be best to use for the build. I planned on using the Hotchkis TVS system (rather than mixing and matching parts), w fox shocks, and1:06 Firm Feel T bars.

For brakes I wanted to use either the Dr Diff kit (13" Cobra) or the 11.75 with Viper calipers. Which brake system would be better?
For the rears (BBP) I have a set of B Body 11" drums already, but wanted to go with the Dr Diff rear disc kit.

Here's where I could use some advice on which parts to use:

1) I plan on using a 73 spool mount K frame, but do have a 72 340 K frame too. Spool mount the best choice?

2) Control Arms (will be reinforced) with sway bar tabs. I have a set of 73's and 71's. (I also have several drag links too: v-8, 6cyl, 73+v8, etc) Is there any advantage to using either one?

3) Spindles. I have a set of 73+ A Body discs, or 70 E body Drums. Can you use the Cuda spindles on an A body, if I went with the Viper calipers?

4) Factory disc proportioning block (73+ disc A body) or use an adjustable one?

When it comes to tire availability is it better to run 17's or 18's?
I plan on using 275's in front and 315's in the rear (The rear is mini tubbed and the front will be modified as needed).
Thanks for the advice ahead of time.