Rustolleum paint job?

Have seen the use of hardener in enamel. It was JD green from the dealer. Friend of mine added the hardener and it turned out with a nice shine. Still looking good about 10 years in.

I have been painting vehicles including, cars, tractors and trucks for 40+ years. The type and brand of paint you use is up to you. The suns rays will fade the paint. A automotive grade paint will hold up longest for this and a WalMart brand will start fading within a year. Using Hardner will help a lot. Not all brands of hardner will work with all paint. I try a little of each in a Dixie cup to make sure it does not turn to "cottage cheese. If not you are good to go. Normally the brand they sell at Tractor Supply works with most. Also remember the hardner is not good to breath in so wear approved mask.
As for reduction go by the label direction. Normally the lower cost store brands are a 10-15% reduction. Automotive style paint is different and some use little to no reduction at all.
Best thing is to follow the label. Then you start with a good foundation.
Hope this helps
Terry

Haven't used the new stuff yet!
At Tractor Supply you can buy the brand Terry is referencing. Also on the shelf is a pint can of reducer that you mix with a gallon. There is also a Hardner which it states will make it shine and not sun fade as quick. I bought a gallon for a John Deere project that hopefully will get sprayed yet this year. I didn't buy the Hardner as I am not a professional painter and am afraid it will harden before I get through it all.
Terry has good knowledge in paint as he used to do body work and painting!
Back in my youth we painted lots of Farm Machinery and Farm trucks with Rustoleum. We used to thin it with the Fish Oil Thinner that Rustoleum sold. Since they EPA forced changed their paint formula I don't believe its as good as the OLD paint.