Left handed bits work great. I never had any until a year ago. Haven't had to use them on a bike yet. But, use then a TON on exhaust manifold studs on customer vehicles!
I prefer that becuase those screws are so small that a drill bit can easily walk into the aluminum of the master. Even with center punching it. Very seldom the screw strip because they are siezed in the threads, I've found. It's usually because they are (A) so soft a metal, and (B) the stretched pressure from the cap pushing against them, holds em tight.