Adding a dash of floetrol to water based paint extends the open time and can help reduce the stipple. I always used a concave end foam roller, laid off with a soft wet brush, but the best ‘straight off the roller’ finish I’ve had is from a Two Fussy Blokes short pile roller, though they’re a but harder to get hold of.
Its Peter Millards' fault im posting this at all, after watching the vids on the cheap paint sprayer i got one for myself and the finish I get has just upped by expectations too far
Thanks for the tips everyone!