Re: Securing canvas mats.
Will they have to be picked up in the new location? And, if you have the room, time, and willing compatriots to re-canvas, then why not velcro them at the same party (an excuse for more sake), excepting the added cost mentioned.
One idea, contrive a way to bind only the outermost mats in place and to one another. This way they will contain the mats within the perimeter without (given the right design) having to attach a fastener of some sort to each and every mat.
Here's another idea, it will take some measuring and a trip to home depot. The numbers I'll use are exchangeable with whatever suit your space the best.
take two 2 X 4's of 4 feet in length, and drill 3 holes at 12 inch intervals through both boards in matching locations.
Now take three equal lengths of rope, tie an adequate knot at the end of each, and feed each through a hole in one of the boards. The ropes should be a few feet longer than the dimension of the mat you are trying to temporarily secure.
Lay down the 2X4 with the three ropes in place, array them to reach across the floor and put each through the holes of the other 2X4
lay down that mats for that section, draw out the slack from the ropes, and somehow fasten said slack in place.
This would allow a cheap, durable, reusable method of keeping your mats together. One drawback is the initial setup, but it doesn't involve needle and thread, so hey. After the learning curve it will be no big deal to set up, like the belt on your dogi.
As I am not familiar with your mats, I can't say how different thickness of rope would transmit through the mats resulting in a ridge surface over the rope. I wouldn't recommend anchor line, but thin nylon, or cotton, something on the order of the diameter of a pencil would go un-noticed under a zebra mat.
It sounds complex, but I hope that's just because i meant to be thorough in language, and I bet it would be cheaper than velcro or tape along each seam.
good luck, and have fun.