If I had time, I'd consider helping you out. Life and the job gets in the way of what I WANT to do. May I suggest that you NOT look for grommets for your silnylon tarp, but other forms of tie-out points such as sewn-on gros-grain ribbon or even self-fabric loops? Grommets add more weight and have a tendendy to rip or pop out. Most of the professional stuff I see appear to go this route.
You could see if Dave at owareusa.com has any blems or slightly used/demo tarps for sale.