Cup 3 wheels - which offset will be best? 28, 48?

[Dasdubber]

I have had a look through all the old posts and have found some good info, however no-one I could find had exactly the same set up as me....

1968 (adjustable) ball joint (not narrowed) swing axle (short axle) pan
CB performance dropped spindles and disc brakes front and rear (With rotohubs)
1963 body with stock gaurds

I plan to run replica cup 3 turbo twist rims all round (all 17x7.5), probably 205/40 front and 215/45 rear. The supplier here in Australia can get 28 or 48 offset - I am trying to figure out which will be best for my application. I figure that the 28 may be best for the rear, and possibly 48 for the front. I am trying to avoid spacers, or at least minimise the width of them if necessary.

Any help is appreciated - sorry to rehash this same topic again.
Cheers
Alan