I have played in both the AFS blackbird at 8’x22.5 and the KT dragonfly surf 8’2”x 22 both are around 130 liter. I am 87 kg dry weight. I love my sabfoil 1350 leviathan and my Cedrus 75 forged aluminum. If your just starting do not go skinny below 21” and do not go small foil. You will have a hard time with 22” wide but it’s possible with effort.
If you are unsure find someone and try theirs. Imagine in a rolling sweep standing on a regular sup and then take 8” to 10” off of it. That’s a 22” board. patience and practice are the key. Like daily paddle in the ocean practice.
I am in South Florida.