As someone who ALSO only really does customs with Mono Eyes (and IBO cuz they just kitbash so nice) really dig the custom overall, cant wait to see more. my last full custom was Gerbera Tetra X Farsia
For the pooling in the shield unfortunately it happens when your spray painting One solution if you dont want to go with weathering is to strip it with 99% isopropyl alcohol Recently stripped a WFM kit that i kinda ruined with clear spray and it worked pretty well There are a couple videos that show how its done
Like the waterslide decals, I assume you're referring to? Well after I was done painting I used Mr. Hobby Semi-Gloss spray on the whole kit, which makes applying it easier than doing it on bare plastic IMO. After the semi-gloss coat, apply them as normal, cut out the decal, in water for 10 - 15 seconds, out of water for 15+ seconds, and apply with a Q-tip and hobby knife. Then I sealed it all in with Mr. Hobby Matte topcoat.