Curtaining is where the paint doesn't dry quickly enough to dry flat so it forms long wide drips before setting. Don't load the paint on too heavily, especially where the gloss underneath won't absorb much moisture. You're better off doing 2 thin coats that dry quickly and will cover all the surface.
You can get away with 1 undercoat and 2 top coats but it's actually easier to do 1 primer, 1 tinted undercoat and 1 top coat. The top coat is so quick to do it's worth doing 2 anyway. I'm quite fussy so I normally stick to 4 coats. The cost of a tinted undercoat is an issue for most diy jobs too.
Curtaining is where the paint doesn't dry quickly enough to dry flat so it forms long wide drips before setting. Don't load the paint on too heavily, especially where the gloss underneath won't absorb much moisture. You're better off doing 2 thin coats that dry quickly and will cover all the surface.
You can get away with 1 undercoat and 2 top coats but it's actually easier to do 1 primer, 1 tinted undercoat and 1 top coat. The top coat is so quick to do it's worth doing 2 anyway. I'm quite fussy so I normally stick to 4 coats. The cost of a tinted undercoat is an issue for most diy jobs too.