Some of this will just be a repeat of the others, but here goes...
As I've mentioned before, I use MM enamels and metalizers exclusively. I also use Minwax clear gloss lacquer exclusively for my gloss coats.
Lacquer over enamel...if the lacquer goes on too thick, too quick, it WILL wrinkle up the underlying paint. I go with a couple mist coats with a few minutes of drying time (dry to the touch), then come back with a heavier coat...never had an issue this way.
Enamel over lacquer...color over the gloss: I've never had a problem.(lacquer being the clear gloos)
In dealing with a metalizer finish...I'll paint the whole airframe starting with a darker base (usually "magnisium") on bare plastic. After that, I'll "marble" a lighter shade (one of the "aluminum" shades), leaving just a little bit of the magnisium still showing(mainly along the panel lines). Then I'll do the same with another shade on a few picked out panels. Once satisfied with the NMF, I seal it with the Minwax gloss lacquer. This helps a LOT when masking for your colors (tail bands, engine cowls, etc.). I still de-tack the tape (Tamiya) by sticking it to the palm of my hand a couple times. When you're done with your colors, peel the tape slowly and gently. Spray another gloss over the colors, decal, gloss over the decals and proceed with weathering. Personally, I don't like anything glossy looking, so I'll put down a good dull coat over everything. For the NMF areas, I'll buff the dull coat with a soft-ish cloth (denim works well), just enough to give the "metal" a little sheen.
Side note..I used to use the Metalizer sealer, which is just gloss lacquer. Bought a quart of Minwax for about the price of two of the little metalizer sealer bottles. I thin it about 50/50 with store brand lacquer thinner. I've done at least 200 builds since switching to the Minwax, and I still have at least 1/2 a quart left. Way, WAY cheaper!!! For the same price, using the "special" metalizer sealer, I would have gotten maybe 5 builds glossed.