You will need some sanding sealer too. Ash has a very deep grain and your gloss topcoat will look pretty lumpy without it.
The rustoleum takes ages to go off, be prepared for a wait. It will stick to rubber until it is fully cured, a matter or weeks.
The clear topcoat you have there doesn't get a great wrap, but you probably won't need it anyway as the gloss level will be nice on the colour coat anyway. I used it once and it didn't go off very nicely, stayed a bit tacky for far too long and didn't have the resilience of the colour coat.
Give the rustoleum enough time, you will get a good hardwearing finish.
If you are going to the big green shed, I'd use the Cabots clear on the neck. This one... the satin is lovely on necks.
https://www.bunnings.com.au/cabot-s-...rosol_p1572096