If you want my opinion, at your weight if I was looking to buy a board for 5-6 bft I would look for a board with the least volume. If you are not interested in jumping and interested in just going fast I would go with a small slalom board say iSonic 86 or 81 of JP slalom 81. If you are interested in jumping then your original choice of jp ss or sb futura is the only one. But remember at 55 kgs you are very light and although the freeride boards are very user friendly and easy to ride I personally think you should look at the smaller slalom boards with the least volume so you don't get bounced around when overpowered. Also bear in mind that the new generation slaloms are quite user freindly and very controllable compared to what we were used to in the past. They are just damn fast and less friendly than the freerides. Are you up for them? And remember no other board performs better in unstable conditions than the slaloms cause they plane earlier and hold their plane longer than any freeride board. As long as you use them in flat to max choppy conditions you'll be fine.