Glass on the outside will not change the amount of water the canoe soaks up to any appreciable degree. That mostly comes from the inside, drips off wet boots, packs, a bit of rain. You'll start off heavier, though, I bet.
Finding cloth? Google.
Myself, I go to a local tentmaker and buy light 10 ounce single-weave cloth. Old time canoe builders used numbered cotton duck like a #12 cloth. It's tighter, stronger, heavier and also harder to stretch over a shape like a canoe. The numbered cloth has two threads together in the weft over and under each single warp thread. The numbered cloth is superior to the ounce cloth in many ways. It's just not as easy for me to get.
For filler, I have lately been following the advice of Rod Tait (I might have his name wrong) of Orca Boats out on the West Coast. he uses a material intended for pipe lagging. It applies easily, smooths well and cures fast. No waiting a month for a cure as with old-fashioned silica fillers. There are dozens of similar products. Here's one:
https://ca.henry.com/roofing/hvac-coati ... ng-coating Takes latex paint and, bonus, adds fire resistance to your canoe.