As I understand it it' s a function of intended use. The "more degrees" you have, the greater the surface area for the locks to "hold on to" the retainer and the greater the load they can withstand. However, that comes with a size restriction and some beehives are so small up top that the retainer doesn't have a lot of space for locks. That and the smaller locks can be significantly lighter. If your rpm range is conservative, say under 5500rpm, the 5° or 7° are fine. If you plan to really rev it and the cam profile is aggressive, the 10° would be the better choice. I'd leave this one open for debate... Pretty much everything I do that needs new retainers gets 10° locks because IMO if you're spending why not get all bases covered.
