Prutser,
Just a thought regarding water getting into the airbox.
Had you considered fitting (or fabricating) an airbox similar to the one supplied by
Moorespeed.
You could fit a tube/pipe to where the air filter locates, then run your 'snorkel' to a higher point, then implement an air filter higher up.
Or alternatively fabricate a cylindrical enclosure, into which the air filter sits, that is then welded to the top of the airbox, then run a 'snorkel' to a higher point on the bike.