Wheel spacer size?

[DieMarthaDie at aol.com]

It's been cruddy out and I've had the flu so I haven't had time to go figure 
this out on my own... I asked once before, but maybe someone else who missed 
the last post has the answer... I have a 1990 V8Q with the G60 brake 
conversion.  Currently it has the stock 15" rims, but sitting in the garage are a set of 
16" factory 5-spokes like you see here 
http://www.audiworld.com/tech/wheel.html with tires and a screaming desire to be on the V8 (thank you eBay).  But 
they're going to need spacers.  How big a spacer and the best source are the 
question of the day.  Any help?

Thanks,
John