With a rocker board you can typically go smaller. He is right about the length and stability. You will probably be fine with either. From GNU's website they don't have a suggest weight chart. I would probably go for the 145 for a little extra stability since you have no desire at this time for park.
Great!! I was tempted to exchange for the smaller one thinking that it would be easier to control. But I'll take whatever size that will help me learn and fall less. Yep, no desire to go to the park, no desire to bomb down too fast at this point either.
Goal is not to catch edges and fall on my ass that much