That should not be a problem in the wheel wells, unless you do allot of
flying upside-down with the gear down, or shall I say UP!
Oh contrare my friend. I am building my airplane in a shop where I covered all windows with black cardboard. No sunlight gets in --- and yes, one year later, the wheel wells are now a disappointingly ugly yellow.
I just wanted you to be forewarned as to the most likely eventual outcome. The sealer product is not cheap, and neither is your time. My recommendation is to take Brent Regan's advise.
"Fuel tank sealer is thick and heavy. On my plane I used catalyzed (two
part) automotive paint in basic white. On the floor and under the
gearbox I sprayed a triple coat. Sides and top got a single coat. The
baggage compartment received a coating of white Zolatone (for texture)
and then automotive paint on top. I sprayed a well reduced WLS primer on
the composite and followed that with the topcoat as soon as the reducer
flashed off. I did not want to sacrifice several sets of fingertips to
sanding the primer. All this was done prior to bonding on the top. Post
bonding I brushed on the seam in the cabin and sprayed the seam on the
right side of the baggage compartment (the one you see).
12 years later, other than a few scratches in the baggage compartment,
everything still looks great. Oil and exhaust stains clean up quickly
with a little brake cleaner and a rag.