I'd say sell the old windsurfing stuff too, but I know you'll only get pennies on the dollar for it. Been there done that
You'll be able to kite twice as much as windsurfing in FL... assuming you shortboard and aren't just cruising around on a longboard.
Regarding the trainer kite topic, I started with a 3m 2-line kite. Then learned to fly a real kite with a couple of lessons and by flying my 12m on the beach in very light wind about 1/2 dozen times. I have always thought that for someone that comes from a sailing/windsurfing background (like us) and already understands the wind and aerodynamics of sails/sailing, the 2-line kite is almost a waste of time... almost. I can see where it helps some, but I've always thought that a small 4-line trainer with sheeting etc would be way more valuable for learning. There's a big difference going from a 3m 2-line to a 12m+ 4-line that you'd use in a lesson. That said, I can see why ppl just get the 2-line; they're cheap and you don't use them much again. If you have the ability to landboard or snowkite, then the 4-line definitely could be the way to go.
p.s. - I also built a landboard during my windsurfing days. I trashed it long ago after converting it to a sled with 4 ski tips
, but now that I kite I wish I still had it! A small 4-line kite would be perfect.
My disclaimer: I've only been kiting for two years, but those are my observations and opinions.