Hi Adrien, hope the team don't mind me answering you
Im guessing that you were on an old wood F156 from about 8-years ago, or a newer (heavier) ASA F156 from the "Formula Experience class".
The ASA F156 was along side the Bic Techno Formula for low cost racing. Manufactures had to keep the design for 5-years to keep costs down for young racers. I opted to use a Bic Techno formula as it felt lighter and faster, but that all changed when generation 2 formula boards came out, AKA Formula 147. At the time, that board was way ahead off all other formula boards like Fanatic, AHD, Bic and MB.
The F156 was 1st generation formula, long, narrower tails. The F156 footstrap position was more inboard c/w newer boards. You will not get the pressure on your heels on F147 or newer boards.
For light wind fun (non-racing), a F147, F158, F159 or F160 can be bought very cheap. All these boards feel light under foot, stiff and easy to control. Plug in a 9m and stock fin and you will have plenty of smiles
But of course, if you come into money, the newer models will be better again.
WC will feel stiffer than wood for sure. Wood will be a bit more forgiving in choppy seas.