Sorry I didn’t supply better info. No, no canvas tarps, just the plastic ones. Most are from Home Depot and are their ‘heavy duty’ ones. They are actually pretty nice: thick, don’t leak water in the rain even after years of use, and are two colors but I always have the brown side showing. The other local big box store’s tarps, for the same size and price, are much more cheaply constructed, very thin, leak pretty quick, and are blue only. I throw those away after use and don't buy them anymore. I do have some carport tarps remnants I’d like to utilize; they were torn / damaged in a storm earlier this year. The biggest piece from that is around 10x20’ before cutting off the damage areas.
None are of the type that are worth taking to an alteration shop, if one was around that could handle them.
Sizes? 8x12’ and a little larger. I do have one large tarp but don’t remember its size (I thought it was a two-pack of tarps on sale but it was just one large tarp, LOL). That one is fine as is.
I do have some stick-to-anything glue but it takes overnight to dry, so that’s out.
Hmmm… How about some double sided carpet tape? That would be a lot easier. Or mini hog rings? I just Googled that and the pliers are $10 USD but the mini rings are $15 a bag. Not sure it’s worth it for an occasional use.