So far the only boss to give me trouble in ++ is, of all things, SIF! I'd get him down to 1/4 or so, then get a tiny bit lazy, and all he has to do is nick me and I'm dead.
I'm trying to do everything, including the usually skipped Upper-Blighttown, and avoid running through areas I normally run through with my other characters. I'll still run Dukes Archives' initial room though.
No spells, of course. I've maxed out a pyro glove but it is for glitch-invaders in the Burg during co-op, against the engine I'm only melee.
What I'm dreading is that soon simple jumps will one-shot me. Like jumping through the circle after ringing Quelaag's bell. I'm sure I'll forget at some point that those jumps take more hp than my guy has and end up back at a distant bonfire.
Not sure if I'll be able to make it all the way to +8. Actually, just thinking of Gwyn, I'm doubting I'll be able to. Eventually he's going to do sooo much damage through my little Dragon Crest Shield.