My usual combat load is 2x R-3R and 4x (occasionally 2x, but rarely) R-60M.
People talk a lot about the draggy double racks but it isn't that big of a tradeoff at all in my experience, and between the weak warhead of the R-60 and the generally chaotic furballs that develop on Cold War servers, I'd rather have the extra sticks. Punch off the racks when empty.
The R-3Rs are useful for killing oblivious cosmonauts or forcing someone to chicken out of a head-on merge, and you can also use fixed beam's ghetto boresight ability to pop someone in a dogfight if you run out of heaters.
R-13s are something I only carry when I'm deliberately trying to make a 'fair' setup for practice against an F-5, or when I'm forced to forsake the R-3R. The extra range and extra explosive power isn't worth the far worse turning ability of the missile, the R-60 is god when it comes to close range.
Any other missile exists only for memes or specific historical setups IMO.