2/4 is where ABC poker is still marginally profitable, but you def have to start mixing in some plays vs the regs to have a good winrate. I can still find a decent amount of tables at 2/4 with 2-3 bad players. 3/6 I honestly never find any tables with less than 4 out of 6 being regulars.

Since I'm practicing pretty consistent table selection recently, I have been regularly including 1/2 tables into my mix.

Saying "I play 2/4" or "I play 3/6" and only opening tables from those stakes is a mistake in my opinion. Unless you are playing at 2 sites at once, I think you usually need to be mixing stakes to have 4 good tables up, unless the games are particularly good that night (which they occasionally are).