I looked through the genuine BMW repair DVD.
I would be tempted to fit an inline HP filter, after looking at the diagrams. Possibly even remove the screen altogether.
Another thought that occurred was replacing the in-tank pump with an inline HP one. Extra tank volume.
Finding somewhere to mount would be the fun part.
I might give this some more thought. I'm tempted to keep the F800 and completely cut it up and rework everything.