I missed the original question, but re filling gaps with epoxy, I do
it all the time 'cause I get gaps all the time!
I have settled on System 3 which also gives you a single epoxy resin
and different hardeners for different cure times. I got System 3's
wood flour, which is very fine and quite light in color. Additionally,
I bought some small jars of System 3's pigmented resins, which are the
epoxy resin part with pigments ground in.
Mixed with resin, even in large amounts, it will look darker because
of a "wetting effect", you know what I mean!? I needed it for some
birchm and added a very small amount of white epoxy resin which made
the mix a bit lighter than the surrounding wood, which is good-
I just happen to use System 3, so that's the one I talk about. 'Course
if S-3 wants to reward me for naming them, I'm right here :-)