In my painting experience, it's always best to stick with the same 'brand' of finish...from primers on up to the clear. Some brands don't intermix or, over time, you'll have some issues. Since you started with Krylon, it's best to finish with it. It won't react with itself and should stick since you steel wooled it and knocked the gloss off. Since you have art on there, shoot a very LIGHT first coat, just 'dusting' the clear on. It will dry quickly since it's light and this will 'seal' the art and prevent runs or bleeding of color. The following coats should be slightly heavier, but still light. Let it flash dry a few minutes between coats. When you have a good build, the final coat can be heavy and more 'wet'. Let it dry at least a day before handling it. I'm not sure what Krylon is...clear acrylic? I use acrylic lacquers, clears, solids and kandies and finish with a poly clearcoat. Maybe they sell a Krylon satin finish? If not, some super fine steel wool will degloss a shiney finish and if you have good build up of clear, you won't cut through. Good luck and yeah, I wanna see a pic.
On the subject of HVLP, when the 'system' first came out, I thought it was crap...the wierd and expensive 'vacuum cleaner' compressor setup did'nt impress me. Later I got a Matson HVLP 'gun'...gravity feed, hooks up to a standard compressor, just use a fatter hose. I had doubts the first time thinking a lot of product is gonna squirt out, but you can adjust it from light to heavy. I was amazed how great this gun was at shooting kandies. When I shot the poly clear, I could lay it on heavy...fast! I'll never shoot conventional again...except my junkie guns for primer. I've been shooting metalflakes lately and I can't shoot the mambo huge flakes...chokes out. So I mix some in with the medium flakes and it works great. I always add pearl powders to the clear for extra shimmer in bright light.
Metalflake flamed Tele I did for a friend