I'm 5'10" 175 and I ride a 184 for my Atomic Patents and Moment Deathwish. I have no justification for this other than I didn't want a super long unwieldy ski and 190 just felt like overkill unless they were huge powder boards.
I haven't ridden the Moment Deathwishes yet but I've always been a 184 guy. I went 190 once for big powder boards out in Utah, and while it wasn't bad, I just felt like I never got used to the length.
I've seen a lot of people going 190 for 5'10" or taller but idk that just seems like a lot of ski.
I'm 5'11 160 and am really happy with my 184 Bibby's. I think your sort of on the borderline between sizes and they'd both work for you. Get the 184 if you want something playful and the 190 if you want to charge.
I'm 5'9" 185lbs, and the 184s feel pretty perfect for me 95% of the time but I think the 190s would be a better option when the chop is super heavy or the snow is deeper due to the extra beef and float. At your size I think you could definitely handle the 190s and might be a bit better served by them than the 184s but you really can't go wrong with either.