Test the gloss beforehand on a piece of cardboard or a ceramic piece that you've constructed to use for testing glosses and finishes. You want to see how the gloss will react to the type of paint that you are finishing your piece with, especially if it's acrylic as opposed to traditional underglaze.
Make sure you have underglazed your piece well before adding the high-gloss spray. Underglazes take at least three coats, if not more, for the colors to come out as bright or dark as you'd like them. Make sure the underglaze is completely dry before firing. This is the final step before adding the high-gloss spray.
When applying the high-gloss spray, apply one coat and then let it dry. Once the first coat has dried, apply at least three coats, drying between each one.
Once the piece has been sprayed, make sure to let the kirin cool completely once the high-gloss piece as been fired. The gloss may crack if the kirin is not completely cooled after firing.