OK, part 2...

The first gun I bought was a cheapie from eBay (basically the same as THIS ONE - except mine $34 at the time).
It actually works just fine and I have only used the 1.4mm nozzle with acrylic lacquer. I would say that technique/experience has probably been the a bigger factor of performance/result then the gun itself.

My second purchase was a small airbrush (also a cheapie from eBay) with the intention of using it for touch ups or small things like headstocks as I thought the "big" gun was overkill and can take more time to clean than to spray a touch up etc. This actually has turned out to be very useful and works very well despite it's $39 price tag, and I don't see the need to repalce it unless it completely craps itself. Mine is dual-action and gravity or suction, which I recommend in an airbrush kit.

My rationale for buying "budget" gear was not wanting to lay out too much if the results didn't prove to be any better than I was gettting with rattle cans, and if it all worked out, I would just upgrade to better quality equipment. What I can confidently say now is that I won't be going back to spray cans.

The last gun I bought is a proper touch up gun (HVLP) so it's bigger than the airbrush and smaller than the 1.4-2.0mm gun. This is what I've used on my last two necks and it's perfect with a .8mm nozzle. I think this will be my first choice on my next build for body and neck.
This is the model and retailer I bought it from: Star 106TG-2.

It's not a Devilbiss or other higher quality brand, but it gets good ratings and suits my needs perfectly. If I was spraying car panels (or guitars) every day, maybe not, but that's not the case. One thing I'll definitely recommend is, if going for a touch up gun, be sure to get one with individually adjustable air and fluid flow.

The main drawback I've found with the no-name cheapie stuff is replacement parts (specifically o-rings). At least Star is a big manufacturer and spares are easily acquired.

Between the 3 type of guns I have I'm pretty sure I could do whatever is needed now. My compressor is a Blackridge (Supercheap) 2.5HP, Belt-Driven, 50L tank, 155L/min. So far I haven't had any problems (2 yrs) and it's reasonably quiet. Probably more than I need but I got a good deal on it and better to have too much than not enough!

If you do end up getting something, I recommend experimenting and practising as much as you can before applying to your first guitar body. Spraying for practise isn't cheap with the cost of paint, but it's the only way to learn, or at least get some feel for how things work.