Here is the (very quick) answer from John Harris, which definitely takes a load off my mind:
We’ve always done it this way, and MAS is still a blush-free epoxy so you can go a few days before overcoating. That’s certainly how our Teardrop was built, as it was never convenient to apply that next coat at the perfect window in the cure cycle.
Chemical bonds ARE better, no disputing that. But I think it’s a case of needing a 200%-strength application, where waiting until the epoxy cures gives you 400% and a chemical bond gives you 500%. We were good at 200%, so all the extra work to get to 500% isn’t really worth the trouble.
There are exceptions. Someone building in a carport in Seattle is going have trouble with fog and rain causing the no-blush MAS epoxy to blush, so they’d have to proceed more along WEST System guidelines.
The rest of us are okay.