Isn't it 16 moves to twist two like that?
It takes me 18. Maybe just because I'm stupid about it, but it's what Macky taught in his old BLD document, which is when I learned it. I always rotate the cube and then do something like (R' U' R U)*2 L (R' U' R U)*2 L'.
I do the same thing, but what's the better way to twist corners? I know some people do sune/u perm and things like that to twist a couple corners at a time, is there an even better way?
There are a number of people who have learned optimal algorithms for a lot of the common cases.
Or, you could do it like Daniel Beyer does, and perform two optimal commutators to fix them in place with just 16 moves (assuming that's possible for the particular case).