So the problem you may have had with the really long hose is that the pressure it said it was putting out at the compressor, probably would have been lower by the time it got to you, and as stated a siphon brush needs much more air anyway compared to a gravity brush. You say your Hubs got a different compressor, but what did he replace it with? If it is tankless (or only has a tiny tank) then it probably won't be able to keep up with the demand for air (even with a gravity fed brush, they should stop selling them as they are not fit for purpose IMO) and could be pulsing, which means you will not be able to get consistent results.
Definately change the paint. If you are not sure what kind of painting you want to do, then I would go for an all rounder/multi surface paint. I do this as I like to do different types of painting and love the Wicked paints. They are great for everything from fabric to automotive and everything in between, they are lightfast and the colours are super bright. But the downside is to get that great colour they are heavily pigmented, which means lots of reduction. It can take some getting used to, but once you get it, they are awesome, and the reducer has lots of other benefits apart form just thinning the paint that makes it worth using. . The equivalent all rounder in E'tac is the private stock line, lots of guys prefer E'tac and these can be reduced with water. If you only want to go the fine art route, then Createx ilustration or E'tac would be better.
As for the airbrush, I am an Iwata fan, and IMO you can't go wrong. However if you are wanting to paint on different surfaces, I would suggest the HP-CS. It is the ultimate all rounder and very similar to the hp-c+, but it has a self centering nozzle and one piece trigger assembly, which makes maintaining a little easier, the nozzle is .35 as opposed to the c+'s .3, so not much difference, just a little more forgiving in the paint reduction department but capable of the same fine lines, and also has up to 2 inch coverage for larger areas. The HP-Cs doesn't have the pre-set handle, however I have never seen the point of them (just my opinion), you need to learn to adjust your control on the trigger as you go along. Apart from that I blieve they are very similar, but the HP-CS is a little cheaper. So may be worth thinking about - either way def a great brush.
Even if you do get everything upgraded (it really will make it much easier to learn) you may still not get immediate perfect paint flow. The conditions in your class, even if you replicated them exactly, may not give you the same results at home. There are so many variables to take into account and even the weather/humidity can affect things. Everyone needs to find their own sweet spot for paint/reduction/flow, that's why there isn't a magic formula where everyone uses the same mixture and psi. However with the suitable equipment it becomes much easier to do. You just need to start with a base for example 1 paint :3 reducer @ 20 psi, and either add more or less reducer drop by drop until you get a smooth line, and larger areas look satiny smooth witout grains. Just remember more reduction = less pressure. Another tip is that possibly 90% or more of paint flow issues can be caused by dirty nozzles. Even the tiniest speck of old paint or a large particle can really throw things off. Even if you think your nozzle is clean, even if you just cleaned it, and it looks spotless, if it isn't spraying right, then it probably isn't clean. Make sure you have some restorer, or cleaner (make sure it doesn't affect any seals, although the Iwatas should be ok as they are teflon) handy. Once you get your sweet spot dialed in nozzle blockage becomes a rare issue.
Getting good equipment and getting your ratios down is 2/3rds of the battle won, and is often the most frustrating. Once that is sorted you can concentrate on technique, and as your class showed you can amaze yourself in a relatively short time with practice.
I have a very similar story to you, I had the wrong/bad equipment, tried ABing and decided I coukldn't do it. Then returned some years later with proper gear, and more info and managed to get somewhere. I am still trying to get somewhere, but it is happening slowly but surely. If I can do it, you can do it, good luck!
