Agree with Dan about coach paints. I've done two cars with it and they came up really good.
A mate did his Viscount and I was impressed enough to do my Ventora.
Painting is best done early when the air is still, less shit flying about, and minimal insect life. I started mine as soon as the sun was up. 5 o'clock If I remember. Best put on a cool car so it doesn't start drying as you're doing it and you then get brush marks. Best to use really good brushes, Hamilton or Purdy pure bristle and you'll need 1, 2 and three inch brushes.
Roof, bonnet and boot is done best with a gloss roller then brushed out. Keeping a wet edge is vital for blending it in and brushing towards it stops what is called shut marks. If any beasties get on it don't be tempted to pick them off until the paint dries, then after at least 24 hrs get the polisher out and you will be pleasantly surprised. Mind you I'm a Painter and so was my Viscount mate, which helps. A lot.
As an aside, I did an Austin 7 for a bloke who went to shows and he wanted it coach painted coz that was how they did them originally. Did a really nice job and he complained he couldn't see the brush marks ffs. He wanted other show types to know it was brushed ,so I did it again, at his expense, with a shit brush and he was happy. It was only the bonnet and boot that was sprayed originally I think.