RE: Leaking canvas
We always put a (water proof?) tarp over are wall tents. We also setup are tents during the middle of summer & apply a good dose of canvac. We buy a tarp that is a little larger than the tent so the whole tent is covered. You need to cut out a hole for your stovepipe, then you are ready for rain or snow.
I would call or email your tent manufacture & ask them what they recommend for a water proof treatment? I have been told that some tents do not require canvac? I was told canvac can even ruin a Davis tent???