Reply to aligning cartridge on headshell

hey would you guys suggest aligning your cartridges on a headshell using a protractor (maybe an audiophile thing) or just doing what the cartridge manufacturer might say (such as align the cartridge to the very rear of the headshell)

thanks
(by protractors im referring to one of these http://www.vinylengine.com/cartridge...tractors.shtml )