The general idea is on a rifle length gas system is to go with a light carrier and buffer. Turn down the gas until it won't lock open on an empty mag, then add a little gas. You have less reciprocating mass which is less felt recoil.
On carbine length systems, the general idea is to go heavy, heavier carrier and buffer. Since the pressure is so high and the unlock time is so soon, it is difficult to reduce the gas enough to make it smooth with a light carrier. It just slams a lighter carrier into the extension. Now gas port size will play into this a lot. If you have a barrel with a smaller port size, then you can reduce enough gas to make a difference.
This is the BCG I run in my rifle length