I'd suggest the following if going for spray rather than rattle can.
1) Find a local painter or paint supplier and going to speak to them to see what they recommend (if already primed take the spec sheet with you)
2) Post here to see if anyone of issues you might have with the system/paint they are suggesting.
3) Buy a small amount (maybe 1/2ltr) and try it out on some scrap or anything flat (with the same primer on it)
4) if all goes well go for it
The reason I suggest the above is having a local supply gives you local knowledge (does the temp/humidity where you are mean you need different settings/paints etc). Talk to any painters in the shop while there and ask their advice as well (best to go visit the shop rather than phone for this very reason). Remember that what works for me might not be any good for your Environment so a local supplier will help in that area.
I believe modern car paints are more than good enough for the kind of flying we do (no long term periods at high level and most cars are left outside in all weathers) so the UV protection should be fine. Given the top aviation product or car paint from a local supplier I personally would chose the latter for the support.
For painting I go for a torch in one hand and the gun in the other, I constantly check I have a full wet looking coat (by shining the torch at an angle so I can see it's reflection) but at the same time applying the minimum paint to get to that gloss look.
A professional will know just by feel how the paint is going on, first time you will need to check as you go.
If anyone says use x, y and z settings great, but only take them as a starting point. Those settings will work great if you are setting up their spray gun for them to use. You will probably need to tune them to your own style and environment.
If it is your first time with a spray gun I'd suggest investing in at least half a litre and trying out different settings to see what they do, then tune it in to get a decent finish. Also do separate sessions and compare what it looks like while painting to how it dries (ie does it run, or does it go patchy/rough). Whatever you use this is most important step to get a decent finish.
I found the interior harder to paint than the rest so far as trying to get an even coat is hard due to all the corners and pieces to paint around meaning that some parts are overlapped several times getting into the corners. Best to go around all the tricky nooks and crannies first and let that flash off (dry for a while) so you can just do a final coat over the top without them running.
I also found my main gun too big to get into some places so I opted for a cheap touch-up gun as they are much smaller.
Spend plenty of time going over how you are going to paint beforehand, as you are going to need to lean in/over/under parts. With the clothing/paint gun and airlines etc you want to avoid leaning over/near painted areas (dust will fall from you onto paint underneath) so have a clear plan before starting.
I opted to have the fuselage at forty five degrees which seemed to work ok, it might be easier on it's side but then you are painting one side from underneath.
Remember that if you are using 2k (two pack) paints then you really do want to be using a fresh air mask.
Painting can be incredibly rewarding or frustrating depending on the results but it is something I'm really glad I chose to do.
Best of luck with whatever method you chose.