Which wheel spacer??

[NW Ranger]

O.K., here's the deal.....

I have a '76 912E, and I bought some boxster wheels (16x 6/7).

I recently got two varying opinions on what spacer size to use on the fronts. One Pelican has an 8mm spacer on a '76 911, and another has a 15mm on a '73 911. Both run 205/55 and225/50.
My questions is this:

Is there a difference, size-wise, between the two cars that would neccessitate a different spacer size?

The 15mm ('73 911) guy says that his size spacer keeps the fronts exactly in line with the rear wheels.

Neither guy uses spacers on the back.

I would like to get this right the first time. Could I get a reading and explanation on what the differences are between the two cars, and which way I should go?

Thanks in advance

Bill

[widgeon13]

I ran 16X7 Boxster wheels all around on my 74 narrow bodied 911, same flares as the 73 and 76 / 912. In the front I had 15mm spacers, I was not aware that you could get 225/50X16 on the back of a narrow body car but I suppose anything is possible if you roll the fender lip and increase neg camber. Hope that info is helpful.