MF trapsin
I think you also posted this q on the community forum.
I think a trapsin with enigma is one of the best mf-ers out there (haven't tried a hammerdin). I currently use this setup and like it a lot.
Shako
Gull dagger (two +3 trap claws on switch)
Enigma
Spirit shield
travs
arachnid mesh
rare +2 trap, +life mf ammy
ravenfrost
nagel
chance guards
gheeds
rest + trap charms, and resist charms.
adds up to 400+ mf. resists are maxed with fade and i end up having something like level 38 lightning sentry. So no major degradation to damage or survivability and still a high level of MF. Since the returns to additional MF start to tail off pretty aggressively around 450, I think that is sort of a sweet spot.
If you don't have enigma, burst of speed is still pretty good for tooling around durance 2. On Meph runs, cast cloak of shadows on Bremm Sparkfist's gang and then draw out Maffer. Give him your shadow master to play with, and then use BOS to boogie around to Meph.
mind blast and cloak of shadows are great for crowd control. you also can take advantage of the various pillars around baal and meph by casting your traps (4 LS, 1 DS), casting SM and then hiding behind them. You have a nice delay between Baal's minions to lay your traps, put your SM in the middle and then hide behind a pillar.
Since you get physical damage from Death Sentry's corpse explosion there are very few monsters that will give you trouble since you can deal fire and lightning damage pretty well. Fire/Light immunes are mainly in trav runs, and occasionally Lister spawns that way. If he does, draw him out, use cloak of shadows and your SM to keep him busy and then boogie on to baal.
Hope that helps.