“ I had printed and followed "Restoration Shop" (I think TCP Global) for ratio of their acrylic enamel, even though I used ALK 200. I also use other brands for the high gloss acrylic enamel hardner and reducer.”
Are you saying you used different brands for data, hardener and reducer?
If so you are very very brave….
Painting is fraught with ways to go sideways even when you are religious out the details.
Using a paint “system” is essential, paint, data sheet, and additives, it is all in the details.
Chuck
