Incredibly confused....backspacing help

[cluxford]

Guys,

I'm so confused. Too much info....

I'll keep it basic (for my sanity)

68 Camaro
AME front clip
DSE minitub rear
rear diff will be shortened

With the AME front end it runs C5 vette rotor and calipre

Going to run a 17 x 7 front rim
5 inch backspace

I have been told the C5 vette calipre requires more clearance, about 1.3"

I told the guy building my wheel and he has built into both front and rear wheels (rears are 17 x 11 again 5" BS) an extra 1.3" Boss (see photo below shows extra 1.3" raised boss...it's on both front and rear rims and obviously means "real" BS is 6.3" instead of 5" from rim back edge to face)

So my questions:
1. Do I need the extra 1.3" boss clearance to clear the C5 calipre
2. If so do I need this on front AND back or only front

I have a feeling I may be screwed and have stuffed this up...expensive exercise if I have got it wrong....