Karl,
You could work on around 7m2 for an F16 and a bit over 8m2 for an F18.
These are just ballpark figures. I have the exact figures stashed away somewhere but these should be close enough to play with.

I would be interested in hearing what you come up with.

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!