Those are fairly close in length, but in short, yes, length/size does matter.
I weigh 175 lb or so, rode a 156 in the powder yesterday morning, and went running back to the base for my 160 with more setback. No comparison...
At your weight I think both or those boards seem a little short.
Ok. I was trying to be funny with the title.
MINUS THE POWDER, just hard pack, groomers, park on small PA hills