Spraying some 2 component paints into molds can be pain. Here is how I do it:
1) Use the fastest hardener & reducer that you can get your hands on.
2) Read the instructions to determine how the paint can be "forced dry". Most Urethanes can be forced dry by either Infared light or short periods of elevated temps after a short purge time. Some high velocity paints can be fully cured with short wave IR light as quickly as 5 minutes.
3) Mist on your first coat and use either IR light or the appropriate elevated temp and time. This with get your mist coat to a point that will prevent it from being softened by the following heavier coats. Your hot box can come in pretty handy
4) Then hit it with a nice flowing coat.
Option 2 - Allow your mist coat to set for a long time before hitting with heavier coats.
Option 3 - is to spray the mold with PVA, let it dry, and then you can spray your flowing coat right away (no misting required).
Option 4 - Use an anti-fisheye agent that is added to the paint. Some manufactures make it and some don't.
Option 5 - Some paints can be put on really heavy till the fisheyes fill. This can cause really long cures times.