What clear coat for Powder Coated and decaled box?

[Focalized]

I have a bunch of powder-coated boxes from Pedal Parts Plus. They already have water-slide decals and look great. I'm wondering what the best kind of clear coat would be best. Also, should I have sanded the box before the decals? Will a clear coat stick to the box as is? I could still lightly sand around the sides because the decals are full faced. Just need to know the safest option to not ruin the work I did.

[plankspank]

I Just clean the powder coated finish with some Isopropyl alcohol to get rid of any dirt & grease. then I apply  water slide decals and let it dry thoroughly to make sure all moisture is gone. Then clear coat the box with a good acrylic clear, using several light coats, letting each coat dry for a few minutes. I like to use Krylon "Triple thick clear glaze" or "Crystal Clear." Let the clear dry good  for several days or longer to harden... Sanding is not necessary.