Well, when you say you're going to "grow into it"...can I ask how old you are? At 5'10" 170, a 158 would be fine for you. If you're gonna grow another few inches a 160 would be a good bet too.
In reality though, you're not going to feel much difference between a 158 or a 160.
Well no I mean weight wise. I used to weigh 185ish when I lifted weights a lot and hopefully will get back up to that size at some point. So I guess I was more curious about the weight guidelines. Cause I may want the shorter board, but like what was said before it is less than an inch. Difference may be unnoticeable to me