For instance: some sub 9ft SUPs can be just as stable as 10ft+. It’s best, however, to go for something between 9ft-10’6ft. The longer the board the better the glide (or momentum) you’ll have. Longer boards also track (point) slightly better meaning less corrective strokes – although you can over board with length and end up with something that’s difficult to turn.
If you’re on the lighter side (sub 80kg) then you’ll get away with widths a little less than 30” – although don’t go too narrow! If you’re bigger boned then 32” would better. Around 190L would be a good starting point for larger individuals whereas 150L-170L for lighter paddlers should be fine.