Replying to On3P Jeffrey Sizing

I am close to saved up for Jeffrey's. But I'm not sure if I should get 176 or 181. I am 5'9" and 145 lb and an advanced skier. I will be using them for all mountain and powder whenever I can get to it. It seems like the obvious choice is 181 but unfortunately I live in Michigan. So the hills I ski aren't all that big. I'm also used to skis around 170 cm long since that is what I use for park so when I'm jibbing around and whatnot, the 176 would feel more comfortable. +k for helpful advice, thanks!