Well, I think I am getting this down... I sanded the roof way down. Wet sanded with 150 and got all the orange peel out.
I got it down to a real smooth flat surface that looks much more like the intended results. probably the equivalent of 3-4 good coats. It took a lot of wet sanding to get it flat and smooth though.

I don't know how I got it on too thick. I measured to the right ratio and it looked right. I think the foam roller might have been an issue. I used a very dense one and I think maybe it didn't spread the paint real well. I also guess that the mineral spirits are evaporating as the paint sits in the tray. So maybe it gets thicker from evaporation as time passes? Needing re-thinning?

I'll try again tomorrow and measure to get the right consistency. Trying a less dense roller too.
I think if I can get a couple more smooth flat coats, I'll have it. Then can let harden and color sand.

There are definitely a lot of variables to control for.