My spray gun technique must be rubbish as I got a lot of orange peel and overspray from the sides onto the top and back.
I'm still learning proper gun technique as well, but I'll say that the results I'm getting with the gun are still better than I got with rattle cans. So that's encouraging at least

Unfortunately I find it an expensive exercise to spray just for practice, but when I do spray, I always do a some test passes on scrap timber or masking paper taped to a big piece of cardboard and experiment with setting and pass technique first.
I am a work in progress.