I've painted several cars and had pretty decent results but there are a few things that I'm still unsure about.

First off, there are places where it isn't easy or practical to sand and buff to get a really smooth finish. Lets say areas like door jambs and engine bays. Is it better to increase the reducer to effectively thin down the paint to cover these areas? If so, I'd suppose that I'd need to make more passes and allow more flash time since thinner paint is more likely to run. What disadvantages are there to this? Does the paint lose gloss when more reducer is used?

Second, I have seen YouTube videos and magazine articles that cover the Cut & Buff process. These guys seem to be starting off with a finish that looks far better than what I ever have. They start with a 1000 grit or finer. I often have enough orange peel to need 600. I use Hook-it pads on my D/A and usually sand wet. My finish work comes out decent but takes awhile. I'm sure if I knew some tips to minimize the orange peel I'd have less "cutting" after the paintwork. I follow the instructions regarding paint mix ratios, I've followed the suggestions of the guys at the paint store too. I've heard of painters increasing the reducer in the final topcoat to get the paint to lay down smoother. Fact is, the hood, roof and trunklids often have minimal peel. It is the sides that need the most work.
Any suggestions on how to reduce the peel would be helpful. I have used PPG, Omni, Shopline, Nason, Lesonal and Sikkens. By far the Nason was the thinnest and had the least peel. PPG products covered the best but seemed to lay on really thick. Varying pressures seemed to have no effect on the amount of orange peel I had, which was the most of all products.

Not a professional painter, but with todays products. Wet sanding/cutting between coats is no longer needed. Did some painting both ways and the paint itself looked a whole lot deeper then the cut/buff method.

Used a product additive called The wet look as advised by the Pavey paints that had some serious profesional painters. No orange peel whats so ever. Did the cut and buff later on a fender repair and it wasnt nearly as nice as the just sprayed fender with the wet look.

The only times that I have ever sanded between coats was when something landed in the paint, like a bug, an eyelash or dirt. I've painted maybe 25 cars since 1997. Each time I learn something.

better spray guns will help,something with a 1.3 fluid tip. don't think its all in the clear coat stage but it starts from the very first coat of sealer. you need to let the paint really flash off good to let the solvents release between every coat and lay down before your next coat. proper temp reducer is a must but you can go to a slower hardener to help the clear flow out more and gloss up. a lot depends on your spray environment. the less air movement you have in your booth the longer it takes for the solvent to release into the atmosphere.solvent travels down through your paint towards the panel until it cant go no further and then travels back up and out.if it sits to long and piles up coat after coat it losens the undercoat up and the paint will take much longer to level out,this is basicly with base coat.if the solvent becomes traped it will kill clearcoat gloss as the solvent will be releasing as the clear is drying.this is what causes dieback and loss of gloss. it will also cause sand scratch swelling because the solvent sat in the panel to long and softened up your primer/sealer.
for urethane single stage I had great results with chroma one ss and a urethane clear mix.what I would do is one full coat of the ss,next coat I would add about 10% activated clear and third coat about 40% activated clear.

You have painted more cars than I, so this is more from what I've learned from others.
Are you getting any runs in the finish? If not, you may be laying the paint down too light or far away.
Try laying it on closer/heavier so it is not as dry as it hits and has a chance to flow out.

Single stage is different than BC/CC too. They each take a different technique.

a good gun helps mix the paint according to man. specs , keep in mind air temps and surface temps affect flash time along with alot of other variables. all else said those paint jobs you see that look almost perfect before sanding and buffing are usually done by people who have painted many cars. they get that good with experience and practice

Runs in the finish? Certainly....Not in every car but often enough to wince each time!
A paint tech told me to spray 6-8" from the panel and always keep moving. My results did improve after trying that.

A really good gun would change your life. Once I found a gun that I loved, I have held on to it for years. The rest as already said is technique and experience. I have never had to use more than 1500 to start out on my cut and buffs, except on maybe a run.

After buff out

I use single stage for engine bays, trunks and door jambs. As to the sanding of the clear-coat I know what you mean. The cars coming from the paint booth often look better than lots of finished products. I think part of the reason is the professional painter probably has heat lamps in their booths. With the lamps they can use a different type of clear than we have to use in our home garage. I just started cutting/buffing my car and was really surprised that i could start out with 2000. I finish with 2500 and am very happy with it.

GREAT Tips, guys! I've painted every car wearing denim shorts or pants and cotton shirts!

my coat has a hoodie,you can use a nylon windbreaker as well.