Label on both the paint and the can of Pentrol will suggest the mix you need.
Is what you are spraying in place? If not, drag it to your nearest autobody shop, slip them a tip over cost of painting your things, and bring it home shiney and new in days. In four states now, my auto body guys have put great painted finishes on stuff that had nothing to do with auto or truck bodies. I just restored an antique baby crib and my guys pimped it out with pin striping for a newborn like you would not believe. Of course the project delayed fender repair for some poor shmuck with a Lexus. I don't really care. And of course the infant will die from paint VOCs.