Best 17" wheel offset?

Hi chaps,
I bought my car with some 17" Rota Splitstreams ......now I've tried to search what ET (offset) and what J the wheels have.
I have found some codes on them but nothing concludent.....I suppose the code "e 45" is related to the offset....but the space between my rear rim and the shock absorber is approx. 5mm.....with an 5 mm spacer.....without the spacer the wheel will rub the shock absorber.
So.....bye bye rear camber adjustment.
On the front part the situation is a little bit better.....the space is approx. 15 mm
Therefore I will need some advice from your side !
What wheel offset.........spacers if needed?!...etc
Any help is much appreciated!

Heeeeeeeeeelllllllllllllooooooooooooooooooooooo

I havent answered ... as dont know to much about it .... it seems its best to go 10mm more spacer on the back than the front it helps understeer ...

Too much negative camber on the rear will increase the rear grip in the corners, thus giving the effect of front under steer as the front will break loose first or so it seems with the pulsar. So too much is not always good thing. I would check the recommended settings that Bob put up ( I think it is titled a good around setup) see how much clearance you have or haven't got on your rear struts then buy spacers to suit.

What's the rim width .
30 to 35 offset rims tend be good for 7<>7.5" widths then easy adjust further with minimal spacers.