Last time I tried I had problems with the color matching and getting the paint/thinner mix right. I also had to put a lot more effort than I expected getting all traces of silicon off the surfaces to be painted.
Given the reliability of modern mechanical and electrical car components , painting is probably the most expensive repair/modification item most owners will ever face-it's a skill well worth having.
If you're doing it yourself you have to accept the fact that you will never get the colour exactly matched. Its just not possible. You'll be buying a can of paint mixed to your paint code which will be very very close.
As for the thinner mix, yes it can be a pain to get it right. Check what the ratio is with the paint manufacturer. Usually 2:1 base to thinner. I found using a plastic shot glass to work well.
Getting it clean sucks. I start with a dry wipe and then a through cleaning with grease and wax remover. Once that dries out use tack cloths. Paint right after.
One big consideration is a clean area to paint. You can't do this outside and expect good results. I clean the crap out of my garage and cover everything in plastic to get rid of the dust since it's toxic. Staple sheets of thin plastic from the joists overhead and you have a decent but ghetto paint booth.
I do primer, base coat and clear coat all separately. I find I get better results that way. Usually 2-3 coats primer, light sand, clean with air and tack cloth. At least 3 coats of base, again clean with tack cloth. Then clear for 3 coats. Let it harden. After a couple days to cure it can be buffed to smooth it out.
Some fun things I learned: nitrile gloves are best. The chemicals will eat vinyl. Those litterily fell off my hands mid job. The chemicals will also eat some other plastics as well. An empty water bottle makes for a great waste paint disposal. For example, when you flush the gun with thinner after or any leftovers.
Your mask is insanely important. I can't stress enough on getting a good one that fits properly. You shouldn't smell a thing through it.if you do, it either needs new cartridges or doesn't fit right. The cartridges should be a combination P100/organic vapor.
