Personally I love the West System for exterior repairs on my house. It is the only material that I have found that meets my criteria for exterior wood patches--as long as there is paint over it.

One thing I would be careful on using it as a topcoat on wood panels is that is made out of bisphenol A epoxy and a phenolic resin. Bisphenol A has incredible durabilty in all cases except for one--exposure to sunlight. The same monomer is used in e-coat, and it is the major reason the material has no exterior durability. (see my posts on that if you wish).

Phenolics do have great durability on wood, but they tend to darken with age.

Normally I do not like urethanes on wood, but a 2k high end yacht varnish like ProLine may work the best for appearance and durability.

There may be some easier to use materials. Check around for some of these.

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2010 Toyota matrix

'93 500 SEL
Well, I sold it. Just got to be too much to keep up with.
First time I haven't owned a MB since 1983.

'12 Volvo S80 T6
Needed something that wasn't as hard to deal with as my bad addiction

'18 Mazda Miata
No more boring cars for everyday transport!