Boxhead,
Quick jacks: The bottom quick jack mount lines up with the existing 20mm hole in chassis rail. The top mount you make up from 50x 50 x 5 angle. The flat of the angle bolts through the floor (inside boot) using the existing body/chassis bolts and top bolt of the quick jack goes through the vertical leg of angle.
Lots of fun drilling holes. Must be done before fuel tank is in.
Clear as mud?
Side vents: Yes you make up 25 x25 x 3 angles and glass/glue to inside of body. If you use Dons(Snakebite) side vents then you need to slightly modify the sides of the body opening. Dons vents are top quality polished SS. I used silastic to hold vents in position..
Fuel Tank. Tank may need to be ADR approved ?? So aluminium drop tank should be done later. I installed my tank with nutserts and side angle as you suggested but chickened out and installed 2X 50mm ss straps as well.
If you get to Shelby Fest you can have a look and take photos.
Phil