Mid gray. SPI grey epoxy reduced as a sealer would work well. If you have some black epoxy you could intermix it with the grey to get it darker. That would help save you a little bit of base if you are trying to economize. Any grey sealer would work though.
It would be very dark. It would take extra coats to get to the true color or what is called "coverage". Meaning that applying additional coats would not affect the actual color. So if I used a mid gray, it might take 3 coats to get coverage. With a black sealer it would take 6 coats probably. Three coats of color over white, grey, and black sealer all will differ some from each other. White, lighter. Black, darker. For that color a mid gray is the ideal choice.What would happen to that dark green color if black spi epoxy sealer was used?
Hooptie/ beaters, any color, when mixing sealer, closer the better. Less coverage equals more base cost. One or two extra coats can mean hundreds of dollars. Doing an all over, jamb overspray edges look less noticeable. An easy way to hold paint sticks next to each other, color to sealer. Light to dark, mix the sealer close as possible. Colors like these are usually transparent. Cheaper base lines are even more transparent, sealer really helps cover. IMO, 2 parts gray to 1 part black, would be a good start.What would be the best color sealer to use under this medium/dark green metallic base?