Ok, got this worked out. You nailed it actually, I was grinding way too fine. I contacted the roaster, and he said he grinds this coffee fairly coarse in general, a little finer than French Press. It was really strange, I usually end up around 15-20 (out of 40 on the Virtuoso) for a pourover, but this range was producing SUPER sour flavors, so I kept tighting up the grind to extract more. Once I tried opening it up more, it was up to a 30 before it tasted good and a 35 before I got any sweetness out of it! Never would have expected that from a dense, light roasted bean, especially one that was so sour at finer grind. Where's my understanding failing me?
PS- Mike I feel ya, they can adjust somewhat but can't compensate for all of the effects.
Prince- That makes sense with the chaff.
Haider- I have both, at around 20g dosed I'll upsize, depends on how much I'm making