As an approximate, every 75 or so points of INT is treated as 1 extra skill level. AFAIK
this is in addition to the standard INT bonus. A +10 Noble staff gives +800 INT.
That being said however, Healing > BoL, always. This is from when i was Staff, and had max BoL and my +10 Noble Staff. My Oracle was STILL outhealing me, and i had a lvl80 charm equipped too. She had no charm, just lvl60 Healing. Healing has a more powerful internal formula. I take that 2000 HP at lvl60 on the skill info page with a VERY LARGE pinch of salt, it's not accurate at all. Healing overall, point for point, just seems to have a better formula.
Take that as you will.