Their product is non-catalyzed which means it never really hardens and will scratch easy and always be susceptible to solvents like gasoline. I have used a product like that before thinking I was going to save money or do something easy but I was never happy with it. I was never tough enough, scratch resistant enough and I could damage it with my thumb nail. Also if you try to sand it down later it will glob up your sandpaper making a huge mess. The globs will stick to your sandpaper and make gouges into the paint making more and more of a mess. The only way I could clean it up was to carefully wet sand it, frequently cleaning my sandpaper and surface.

A proper product will include p-sheets that will answer all of your questions. In the past I have used the restoration shop and kustom shop products sold by www.tcpglobal.com with good results. They have p-sheets on their website which tell you all the pertinent info like mix ratios, compatible substrates, surface prep, grit, application techniques, gun tip size and air pressure, etc. Their gallon kits of single stage urethane prepackaged colors are like $120 each and layed down real smooth even with my cheapie spray gun. I thought my results were kind of hum-ho until I went into the chevy dealer for parts for work one day and noticed how much smoother my single stage job was than the OEM clear coat on the corvette and camaros they had in their showroom!

I'm just a backyard hack but the only time I have prepped with 1000 grit has been if I've been scuffing base coat to re-clear an existing panel. Normally I do 400 before hosing on the single stage paint.