Well, if you speak of Paasche, I must admit that :
_ they have a wonderful commercial department (reasonable prices, easy to buy even overseas, nice people)
_Every double action of theirs that I personally tried or even owned was crap, with one exception though : the AB model which I find great, specially the older ones with the green handle ( I own two and not willing to throw those ones ) .
I think you'll be happy with with any top Iwata, but let me tell you a short story : I owned a HP CH that I sold to a friend to buy a CM C+; I got my CM C+ ...and I finally also bought another HP CH. In fact, it is obviously subjective but I prefer the action of the HP CH ( and I don't like the grip of Badger 150 either ) . They are very close anyway. If needle/nozzle gauge means something, I think CM C is 0.18, CM C+ is 0.23 and HP CH is 0.30. I don't know if the CM C is still produced but as far as I remember, gauge adaptation can be made ( 0.18 set on a CM C+, for instance ). For the record, the tiniest gauge I know is 0.12 on Aerograph Sprite, did not try yet as mine are mounted in 0.15 or bigger. As for hairlines, Custom Micron surely will do. Sotar also but I would not try on my Sotar what I did on my CM. Just to puzzle you a bit more, you could consider Harder & Steenbeck Evolution ( or Grafo but it's a bit different ) which is very "modular" as for needle gauge, cup size, the only needle traveler limiter I know that can be switched on/off, Fine Pressure Control ( same stuff as the MAC valve of Iwata ) and some more.
Let's face the facts, chap : life can be very hard when time comes to choose another top airbrush.