In Post #2 above, I gave a word description of how I switched the air inlet to the side grate behind the passenger roll bar. This was a two part problem - first is sealing all the openings to the snorkel other than the side grate. Where possible, I inserted metal pieces fastened with sealer/caulk. The idea was to still be able to remove the fender liner without breaking adhesive joints. First was to seal the lower front of the fender liner.
The curved part butts up to the roll cage tube when installed. Next was a piece to enclose the remainder of the roll cage tube. It was glued to the front and side of the roll cage tube. You could possibly use expanding foam insulation here. The key is to seal off around the roll cage tube where the bottom of the fender liner mates up to the roll tube.
Another big dirt inlet is the flared area right behind the passenger door. One opening is already sealed. The other got the following part.
The area where this goes has surfaces going every which way. The down side in the photo goes forward.
Another major inlet when the fender liner is installed is around the passenger seat belt retractor. Narrow side is glued to the back of the cockpit below the retractor. It is bent to seal against the fender liner when liner is installed.
Near the center of the seat back is a 1/2" wide, 10" long gap between the fender liner. I did not find a good solution for this. When the fender liner was installed, I reached through the side grate opening and installed Gorilla tape to bridge the gap. There is also a gap running front to back where the fender liner meets the fender. This got tape also.
There is a gap in the back of the fender liner where there is a cutout for the tail light wiring. Also several gaps between the liner and the fender. These were all closed with Gorilla tape which nicely matched the fender liner cover.
In each of these leak sources, the better you match your metal piece or tape, the better the outcome.