Hey Joe, I'll get with you at the next meeting, but it sounds like you might have the wrong needle/tip combo in the first issue [no paint on fine tip / drip on large].
For the secodn issue with the tamiya paint, sounds like it might be the compressor. That silent one I picked up online only flows about 20psi, but its not constant. And I cannot seem to get it to work right with the 150. The new compressor I picked up can flow a max of 45psi, but it is CFM. I got it at Harbor Freight down off Army Post. They ahve two versions, its quiet, and very nice.
As for the third issue with the paint flowing back into the cup, I get it too. The thing is, there is a small alcove, if you will, inside the 150. The paint collects there, and even spraying through thinner doesnt get it all. So when you cut the air flow, gravity kicks in and the thinner/paint flows back into the cup. thats why I recommend a thorough cleaning after every use. something I dont usually do, and now I have to order some parts for my 150.
See ya tomorrow night.