If I had water getting between the metal and walnut veneer , I would be asking WTF was happening somewhere else.
.
I left the quarter light open during a storm. The channel in the plastic into which the trim piece slides retains the water and it travels along with capillary action. If there is any way in, it'll find it. As it did with me. I used epoxy to join veneer to aluminium. I should have used the type of lacquer you did. The flat pieces were easy, the curved bit a bloody nightmare.
I did the console in two parts. I cut-out and veneered the dished bit where the handbrake goes and covered the rest in black vinyl. The result was pretty good in a factory sort of way and not "too much wood"
I liked the look and I'm not a purest. I just preferred the original. The P6 is very much a sum of period technology inside and out which never really existed anywhere else. Inside it's kind of a unique transition between traditional and modern that's every bit as distinct as the oddball suspension. There's a feel and smell and that gets lost if you change it. Sometimes you have no choice - the reason "they don't make them that that anymore" is materials have improved and few cars looked as grotty with neglect. Genuinely good original trim is near impossible.
That was "restoration porn" in a good way BTW. referring to the seats.