[BTirish]

I think a raise on 4th is good. There's a lot less value in slowplaying 3 of a kind, even heads up, in hi lo stud--right?

How aggressive is the opponent? Would he bet out without a made low on 5th into likely trips? This is one reason, results-oriented perhaps, for raising 4th.

I suck at this game, so I don't know whether it's possible to fold at any point. If it is, I lay it down on 5th--it's possible you're letting him free roll or even that you're drawing to half.