There are a few Sunwuko build:

1. Genwuko - Among the most popular
2. Bellwuko - Spam bell for damage as well as proc decoy.
3. Hexwuko - Hex pant and TR and spam mantra to proc

I tested all 3 builds. Easiest T6 farming should be Hexwuko. You need to build up passive spirit regen as well as Guardian Path. Hexing pant will provide enough passive spirit regen while you just keep TR and occasionally Epiphany. Spam Mantra from time to time to proc decoy. Since TR pass thru everything, you don't really need to stop or DS or Serenity. Problem with this build, it's getting hard as you move into higher Grift which require more spirit that just passive spirit. It's still fun in T6.

Then I tested Bellwuko, you need FoT - Quicken for fast spirit regen. Once it's full, spam it. Most E die within seconds in T6 as you spam bell and proc at the same time.

My current build is Genwuko. It's better in term of damage output since you just focus in generating spirit using FoT / WoTHF while keep spamming Mantra and Sweeping Wind. For this build, you must not use Inna set since it will reduced Sweeping Wind from 75 to 15. Just keep punching thing to generate spirit and with the spirit spam mantra and win! Most high end build are based on Genwuko. The Flying Dragon is best choice in this case since there is chance that it will double your speed. More speed, more spirit. Legendary gem to aim for is Gogok and Mirinae.