I'm curious why you prefer to rake leaves onto cloth? Plastic tarps drag easy...
I work for a tent company and we use the heavy duty nylon tarps exclusively. We lay them out and drage them across every surface imaginable to preserve the tent vinyl. A canvas tarp is going to be heavier, especially when wet. and they will mold easily.
Im a landscaper and we do tons of leaf cleanups I get old pool covers the kind where they put the springs on they are super durable and they have sewn in seams so you can make
Them whatever size you want . I drag them with my zero turn loaded with wet leaves
And they still last a couple seasons . Go to a pool supply and ask for one that they took off
A customers pool and replaced with new
I assume you're dragging this with a machine...
I do the same thing on my 2 acres of leaf-covered lawn only I don't tow it by the corners--I lace the grommets into a giant "burrito" and drag it by the end. Never had a seam blow out in 22 years of doing this. One thing: wad up the tarp around a tennis ball where you tie the drag rope & you'll never tear another hem, either.
Great tip about the pool cover, btw!
Ebay...
I got tired of going through a plastic tarp twice a years on my crawler and project trucks. They are stored in the sun, close to the ocean. Very harsh conditions. I bought two good quality canvas tarps on Ebay and they have been holding up great for years. They are expensive, but worth every penny.
This is the company I used
http://www.ebay.com/itm/10-x-12-Canvas-Tarp-18-oz-Extra-Heavy-Duty-Tarpaulin-Water-Resistant-/150819609496?var=&hash=item231d8c9b98:m:m4n_MA8HjVQ4mDDwli9Epew