A big thank you for all your advices, it helped me to understand what would be the ultimate prone board for my use, proning medium power waves with white wash hits. Hopefully this thread can help other people out there.
The top designs I was looking at were the Black Eagle from JS, the Amos Raptor, the Firebolt from Amundson, the Armstrong FG.
Living in south portugal, I opted to talk with Jorrit from Appletree as I love their construction, and he was kind enough to come up with a new design that checks all the boxes and more, a true masterpiece. They normally do not do entirely new designs for a customer, they can adapt exisiting templates.
The resulting custom is a 4'6, 18.5" wide, 6.6mm thick, 32.5 liters, 2.8kg.
- Widest point forward and pulled out tail : for good paddling and avoiding rails touchdown during tight turns, largely inspired from Adam Bennets and Kane de Wilde iterations.
- Decent entry rocker, soft bottom rails at the front, sharper rails at the back : for foam hits and touchdowns, to release the water at the back, Jorrit made the whole design.
- Long (32cm, experimental) and forward foil box : for less swing weight at the front and foil compatibility, inspired from Armstrong boards.
- Recessed deck : to have a 0 degree angle of the deck and foil box.
First sessions on it feel right on point, doing everything I wanted and more. Paddling great for its size, feels very lively and loose in turns, when hitting the white wash it behaves like a shortboard, and the tail keeps releasing the water. The ultimate prone board for my use, calling it the white eagle ;)
Again, thanks for all your advices and feedback, the foiling community is a true blessing!