I herc'd my TJ about 6 months ago. Came out great and is holding up as advertised.
TWO coats. One thin one and after curing until it's not tacky anymore, a second thick coat (per herculiner's directions).
One can did both coats in my tub from the firewall (as high as I could go) to the tailgate (including the inside vertical part of the tailgate) with a 1/2 pint left over. It retains dust but I don't care.