You have a few options.
1. Ignore all CI's and teleport past them. Dangerous if poorly equipped.
2. Go back to NM and level up into the 70's with baal runs.
3. Depends on your mercenary. Use telekenesis to knockback CI's against a wall and let the merc deal with them. Can the merc survive at that level?
I like might mercs, but a HF merc could do as well. What equipment is he wearing?
Welcome to the SPF!
Actually I agree with you. Resists are problem when entering hell, but that problem tends to solve itself while the merc gains levels. But you forgot to mention CBF (cannot be frozen) and IAS (increased attack speed=more leech and more damage)When it comes to mercenary use the following priority list and try to fulfil as many of the points as possible with the gear you find:
1. Life leech
3. High damage/fast attack weapon (this includes chance of crushing blow)
4. Physical Damage reduction
5. Faster hit recovery
(I guess someone will alter the priorities in this list pretty soon. This is the order I follow though)