Well you just need to pick your fights and position as best as you can when you have to fight more than one person... I think Stealth is important for VS, but on this one I didn't bother with it at all.
My other win with VS had 27 stealth (mostly for the ninja title, I'll admit... I didn't do any stabbing) I try and do Zot slowly every time, trying to only pull and dispatch one monster at a time (well, except for the draconian packs which I still try to disperse, especially if the layout allows for messing around with LOS). By the way I'm sure a good vampiric weapon (against foes where it's applicable) and magic drain along with gspirit are quite nice methods of healing (+regen 3) even though I wasn't tanky because of my lacklustre armour and low defensive skills.