RE: Formula Windsurf and Formula Experience
Coming down form a Start to a Carve 144 for a 76 Kg. sailor should not be too much of a problem, but are you using the hired Starts with the centerboard/centerfin......or not?
The FE board might be a good choice too, but you need a much larger rig to make the FE (and Formula boards) work in 8-15 knot winds.
The Carve 144 (even with a huge ,5-9.0 m2 rig) isn't going to be doing much in < 12 knots of wind.
Are you ready (as in you've already tried them) for big 8.0 m2 and greater rigs?
If yes, you would be good to go on the Carve 144 or FE.
If no, then you need to take some big rigs out and see how you like the added weight and power before you select your rig sizes for the sails you will be buying to power your new board.
If you sail in winds over 12 knots, then a 7.5 m2 would get you planing, so an even smaller board might be OK for your weight.
A bit more difficult to learn on, but you are a "weekend warrior in shape, hehehe." so you will probably be able to use the skills you've learned to begin some good progress.
So, overall, I think the Carve 144 makes more sense as it doesn't require the really big rigs for full performance.
Get a quiver of 8.5/7.5/6.5 and you should be quite happy up to 18-20 knots on the Carve 144 in flat water.
Since you are light, you can get a smaller 100-115 liter board for the 6.5 and higher winds.
Hope this helps,