Thinning will mean that you need to add multiple thinner coats to avoid the product dripping. Try to aim for a product slightly thicker than you might normally want when applying an automotive coating. Additional coats can generally be applied after 30-60 minutes depending on the air and surface temperature primarily. The surface will still be soft, and may be slightly tacky, but as long as you don’t overdo the lacquer thinner should not sag with another thin coat. The lacquer thinner is generally the wildcard, since it is a variable we cannot control and it must actually dry whereas our products will cure, not dry.
You can find additional instructions, recommended supplies, and other helpful advice which can be downloaded and printed at: https://spray-lining.net/polyurea-application-instructions/ as well.