It's all a matter of preference. A 157 will work for you great. A 161 will work for you great. Which is better just depends on what you want your board to feel like / do for you.
I'm 6'4'' 210 and ride a 161.5 TRice for everything, including deep powder, so I do think that a 157 TRS or Legacy would be plenty for you. However, if you want more of a bomber board and you're more concerned with powder float and stability than quick turns and playfulness, then the 161 might be better for you. But if that's what you're looking for, then a Dark Series or Heritage would probably be better boards anyway.