Round 3 was the only round that I ran this year, and I went with my untwinked 99er Druid, Septimus. Standard gear for a Windy (summary below), except maybe the Bloodfist to hit 99 FHR breakpoint with HotO flail.
He ended up with high MF (382) due to not really needing slots for other things, with Cyclone Armor allowing barely positive-to-low negative resists and plenty of vita even when the Oak poofed, with BO helping on the mana front. If I had more skillers, he would not have used MF SCs, and a second +skill ring would replace the Nagelring if he had one.
Helm - Shako with pTopaz
Amulet - 2/9 caster amulet with little else of use
Weapon - Hoto (34@) / Spirit (35 FCR)
Switch - CtA (4 BO) / Spirit
Body - Enigma
Gloves - Bloodfist
Rings - SoJ and Nagel (30 MF)
Belt - Arachnid
Boots - War Traveler (33 MF)
Charms - 3 skillers, Gheeds, FHR/life/MF SCs
Merc - HF, Andy's (unsocketed), Treachery, Reapers (unsocketed)
This guy is super safe in the Pit, and I think he dropped below 1000 life only once across the ~28 hours. Mana burn is an annoyance, but I kept a row of mana pots and made sure to pick some up as I went. He could also safely drop one of the three rows of full purples for a second row of mana to avoid the stray time I emptied the mana pot slot and got mana burned before I could a mana pot up, but it was easy enough to use a purple.
Based on XP progress over 28.5 hours, he was just over 6M/hr, which is really slow. But I was the one who chose Pit runs over Baal