I'm under the impression that 6max merely necessitates a looser, more aggressive style of play due to the more blinds you pay and the fact that you can get away with it due to having fewer people likely beat your hand.

Reads also seem much more important because the extra looseness and aggression means players will more often butt heads with marginal holdings. I guess that's also why there's more variance with 6max.

But my curiosity goes a little deeper than that. There are mid-stakes forums here on FTR for both shorthanded and full-ring games. Is the difference between the two kind of like the difference between tournament and cash, or even LHE and NLHE? That is, should I decide early which one I want to most improve at and just go with one?

It seems like there's no way I could hope to 20-table 6max as I move up like I've been doing with FR. Should I just stick with FR, then?