I can stay alive by spamming rof or ps and get heal from divine favour. I didn't use 55 but I use 135 or up (I don't remember the exact number of my hp but I only use 4 sup 1 normal).
Mo/D with 3 ranks in earth, full bar of enchantments and Mystic Regen? This nets you a regen of 16, possibly 14 if you cant keep SoJ up or something similar. This combined with DF should be enough to keep you alive. Or you could just put more ranks in Earth