You can get a protractor that works with your Rega arm at:
http://www.vinylengine.com/cartridge-alignment-protractors.shtml
Also, I purchased a Mint and recently did the alignment on my Rega P9, big difference... really sounds good.
http://www.vinylengine.com/cartridge-alignment-protractors.shtml
Also, I purchased a Mint and recently did the alignment on my Rega P9, big difference... really sounds good.