I recommend checking this out:
Informative on the boards, but also a bunch of other interesting things...I was pleasantly surprised and impressed hearing him speak.
It also got be me intrigued about the E3 boards.
Looking into it a little, there's 2 versions, one for downwinding, one for winging. The downwinding one is a bit extreme, very specific to that...too narrow to standup paddle effectively, intended to be knee paddled, then hop up once ready to take off. It is longer than ideal for winging or sup foiling.
The wing version is a lot less extreme and starts to look like typical wing board dimensions, but a different profile with width forward, pulled in tail, and that unique pointy tip.
I am looking for a sup foil that is also a light wind wing option ... so feel like the optimal might be somewhere in between the two