RE: the right board for me
At 200 lbs. the Carve 161 sounds like a very good board for your to advance to. It has significant "down the road" possibilites in lighter winds.
Eventually you will want a smaller lower volume board for winds over 18 knots, but going too small initially may make your learning curve quite difficult.
What sort of 180 liter board were you sailing? Wide style (SB Start, SB GO, Bic Nova, Exocet Cruiser...?
Hope this helps,