A grizzly added a door, a window and a sky-light to a wall tent I now own. (No blood was spilt) I can bring the canvas back close together with some stiching but then it will need some patching to be waterproof. What do I use to patch a canvas wall tent?

Is there an iron on type patch or is glue on best? What kind of glue? Need I put patch on both sides or just outside?

Robin.