You first need to find the frame that is most comfortable to your body, no matter who the manufacturer is. Try on as many as you can, with some weight, to see what feels best to you. I know that's easier said than done. For me, that's Mystery Ranch Guide Light MT. For others, it's SG, Kifaru, Evo, whatever. It's very subjective to each individual's body shape. Choosing a bag for that frame is secondary to making sure you get a great fit.
What he said.