As for a “waterproofing” we don’t recommend putting anything on our tents.  About the only time we hear of one of our tents leaking somebody has “retreated” it. Our canvas is so tightly woven that we very rarely hear of anybody having a problem with the tent leaking. When we do hear issues with leaking it is typically because something has been done to effect the existing treatments.

If you want to treat your tent we sell waterproofing by the gallon.

A rain fly will also keep you dry.