Always try to use the best quality paint you are willing to pay for. Dulux trade is a good example.
if using satin, go with a smaller 4" foam gloss roller and apply thinly over the top half of the door and then use your fine/firm tipped brush to lay off the rolled on paint, before its settling. then do the same for the bottom half of the door slightly overlapping the top & bottom with the brush strokes to bring into 1. Satins & eggshells need a firmer brush stroke & gloss a lighter stroke. Always with the tips if the brush.