Got my WhirlyBarb up to running GR 75 or so, T16, so basically she's "done". She's now my go-to Bounty runner, just because she moves so fast. At this point, it's just a matter of finding Ancient gear, buffing them up, pushing for higher GR levels, etc.
Along the way, she'd managed to collect all the new Barb set pieces. I'd forgotten that Barbs got a new set, too, which cranks up Frenzy. I tried it out, kinda half-assed, by converting my Whirly setup to Frenzy, but it wasn't working, so I switched back to Whirly. Then an Ancient Bastion's Revered dropped (Frenzy stacks 10 times instead of 5, plus some other weird bonus that I can't remember right now), so I figured I'd give it another shot.
It made a huge difference, as you might expect. Basically it makes the build, although the Ancient Undisputed Champion (Frenzy gains the effects of every rune, plus cranks the damage) I already had certainly helped. I like to try to figure out my own builds when I can, see how far I can get, before peeking at the IcyVeins build guides, and I haven't peeked yet. Managed to run some GR75 and she ran some T16 cows, so I figure she's doing alright.