Great thread. There are so many different floor designs and so many thing to think about when choosing one.
I took my inspiration from https://mattsfishingblog.com/tinny-pimp-project/
This design is simple to make (if you are good with a hacksaw and rivets), strong, allows for a floor hatch, no gaps under the seats, clean look as it hides the floors supporting ribs.
ps ive only made the frame so far. Marine ply floor to follow soon