have not used the canvak but have thought of it ?
the other stuff I would not use though ! ?
seam stuff I have seen is in a bottle that has a dobber or little foamy thing on it and you roll it on the seams like those instant shoe shine bottles or you use a small brush
ditto the get the tent wet and dry then wet and dry say 3x if you can set it up in your yard use a hose with a spray attachment thingy
and get it all wet let it dry do it again and again
basically you are kinda washing jeans in a way making the fibers swell and relax which makes them softer in a sense to expand quicker when it rains
the canvak though I have heard is good stuff ? I just have yet to get it ? on the South African site I think is where I read some people use it after they have the tent for a few years to rejuvenate the tent and since all of us conqueror owners know are tents are a few years old this was my reasoning for wanting to try the stuff