Ok so with Golden Nekker decks, max unit is 9… which means you can actually slam Mutagenerator on 9 provision units pretty consistently, doing something like 9 provision + 4 provision. Or you can also use it on 8 or 7 provision units.
On top of that, you can use Golden Nekker to pull Mutagenerator extremely consistently if you don't draw it, as you are likely to draw Nekker or Arcane Tome.
I've tried a few different variations, here's where I am at now:
I've also tried the shield package. Haven't gone down to 8 or 7 provisions yet. For this list, I'm probably going to cut Anna and one Kerack Frigate which allows me to add another 9 and 4 provision unit.
Source: https://www.reddit.com/r/gwent/comments/w668ev/golden_nekker_mutagenerator_need_ideas/
