For solo Sammy I think the best three options are Twohitback, Powerstrike, and Retribution.
I don’t think stat points affect abilities, but the more Int you have the more your heal charm would heal for, and in turn the more a healing ability would do. I have never used healing abilities so I really have no idea. :D
I haven’t played Sammy in a while so don’t remember exactly how I played him, but I’d get twohitback to 50+ then work on powerstrike and ret. Retribution is triggered by hits taken, so if a monster hits you for 0 (this will happen more if you’re using an EE armor) you won’t have a chance of it powering up. If you choose to do three abilities, I’d probably do retribution last. Twohitback -> Powerstrike -> Retribution
Great advice

I have already messed this run up a bit by waiting too long before stating into vitality, so I might just accept that this first samurai climb is going to be a slog and test out a healing ability. This way I can get it out of my system and never use it again