Please do not use gasoline to make your sil solution. Far too dangerous.
Mineral spirits and 100% silicone caulk will work when THOROUGHLY mixed in the right proportions. IMHO the dunk and squeeze method is best because it forces the solution through the fabric, saturating every thread.
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Waterproofed it tonight by dunking it in a mix of GE 100% clear silicone and odorless mineral spirits. The contents of one tube is 300g so I mixed it with 900g of spirits. Used a bent rod in a drill to mix the solution. Dipped and kneaded the tarp in the solution until it was all soaked. Hung one end of rigeline tie out to my hammock stand and then slid hands down the tarp as it came out of the bucket, squeezing out the solution. It's hanging out to dry. Will provide update tomorrow.