What is the best barb setup for trying to reach level 99? Would this be a dual Grief PB for max damage/clear speed, or a Grief/Last Wish?

What about merc setup (Act 2/Act 5 - and items)?

Dual grief pb
Gface
Enigma
Gores
Highlords
Arach
10 fcr ring
2x hoto swap for fastest tele
Raven frost

Max ar charms
Act 2 might merc
With reapers Fort Andy’s. Or you could use pride Fort Andy’s as well.

I prefer zerker and target boss packs. Similar clear as ww but alot safer since you dont get fucked by amp, might undead that you cant leech off of:
gface cham
grief pb
pheonix mon
arach
loh
gores
hlords
x2 fcr rings with mana and leech

mar/ar chamrs

pride might merc with fort andy

Alternatively a double throw setup is better than ww for density clears but it's a bit more expensive and complicated to set up since there a a lot of setups and each one will depend on the rare eth weapons you have available and on the area you are clearing.

This. But both are good.

Thanks everyone. Is whirl wind or frenzy the better route?

Ww. It’s that or zerk. WW has more aoe. Frenzy is fun for a bit but also very boring

use ondals and leech