Sharing wheels between Mini Cooper and beetle?

[Bugs]

Ive done some research here, and trying to fully understand what i want/need to do to put some 17" wheels on my 1974 standard beetle.

In reading I have noted that the 205/45/17 rubber that is on my 4x100 wheels which are mounted to my 2002 MINI CoopeRS is the ideal tire size for my bug..

The hard thing im trying to figure out is the whole backspacing with/without spacers in order to make them work.

My car is a 1974 standard beetle, front end lowered 2-2.5" using an adjustable front beam, and will soon have the rear lowered to match. Also, will be using stock fenders from my car.

In order to run 17x7 or 7.5" wheels on my Bug, with 205/45 tires, what is the ideal backspacing to run to go without spacers? And if i decide to share wheels with my MINI (which have a ET40 / 5.75" backspace) what (if any) spacers would i need front/rear to make it work smoothly and not have to worry about damaging my wheels/fenders/etc

thanks in advance.
Ive searched, and spent the last 3 nights reading everything i can find relevant but have had no luck finding exactly what i want.