A lot of people will tell you that it's table-dependent. I could go as low as Sklansky suggests against a tight table, but generally, I don't go quite as low with pocket pairs (maybe down to 88), suited connectors (JTs), or Axs (down to A8s, maybe?). But I'm a little on the tight side.

Generally, I've noticed that aggression, particularly PF aggression tends to be a little higher in 6-max, so I'm going to be a little more cautious UTG 6-max than I would be in MP full-ring. But it's close.