Wheel spacers 20mm or 15mm??

[TyperItr]

I am thinking of getting some wheel spacers and I have done up a simple calculation to make sure I have it correct. I am just putting this out here form someone to either correct me of confirm what I am thinking.

I have 8.5" rims on the car. However the new wheels I just got are 7.5 but I want to keep the same "arch filled" look. They are the same offset +42

8.5" = 216 mm. The centre is at 108 mm. +42 offset = 108+42 = 150 . So there is 150mm of the rim behind the hub. This means the wheel is out 66 mm
7.5" = 190.5 mm. The Centre is at 95 mm. +42 offset = 95+42 = 137 . So there is 137mm of the rim behind the hub. This means the wheel is out 53.5 mm

This means technically for the same look I need a spacer of 12.5 mm, but 15 mm will do. But a 225 tyre may rub then? I know with an 8.5" rim the 225 does not rub. However that is due to a very small stretch on the side wall of the tyre. The 7.5" rim will cause the tyre to have a steeper side wall which may cause some rub?

Would 20 mm be too big?

 

[C&S Evo7]

with the spacer you effectively you will be running 7.5 et27 so wheel would be out 68mm with that and the squarer sidewall thetyres could be very close

 

[TyperItr]

Thanks, I can get a good deal on a set of 20mm spacers.

Has anybody got any experience of running 20mm spacers? If so what size rims and tyres were you using. I think 15mm is the better option but i can get the 20mm for half the price!