No time to be flipping rate switches in combat. You could use them for landing and take-off I suppose, and maybe some guys do.

Personally, I disable all the switches on my TX in combat configuration, less things to knock in the wrong direction at the wrong time.

Instead, I use a lot of expo. This allows me to let the plane groove when I need to, and move quickly when I need to. However, this isn't universal at all.

Roll and pitch rates are very much person preferences. Some guys like lightening fast roll rates, others go for a slower roll rate to make it easier to get just the right angle to nail somene. Personally, my roll rate is slower than many I've seen, but it doesn't hurt my scoring any. Pitch, on the other hand, is as much as I can manage, turn radius, after all, is everything.