Hi Francone,
Basically you are in the same boat I was in several years ago.I moved down from an Exocet Cruiser 205lt to a rrd 360 evolution 155lt quite quickly. I kept the rrd for nearly a year then moved down to a Futura 133 (Bloody fantastic board that I still use in sub 20 knot winds) but I found that at my low skill level things happened in a hell of a hurry.
I have a Futura 111 that is my board of choice now and a 94 isonic that i have yet to master. It is quite frustrating learning to ride smaller boards (especially as you get older) BUT....the rewards are fantastic.
180 to 145 is probably a good call as you should still be able to uphaul if reqd and you should get planing in the right conditions without to much trouble.
A narrower board will give you an easier ride as the wind speed increases thereby decreasing the fear level,a wide board in high winds can be downright frightening.
At a 3/10 dont go too small, just enough to take you out of your comfort zone and it will take you the next season to get back in, then do it all over again.
It's all about enjoying yourself.

