I've seen posts talking about the candlewax solution not working that well. It doesn't distribute very well but I have no doubt that it'd work great if it would. WD-40 -- bad (petroleum based). LPS -- good (stands for 'Liquid Polymer Silicone'). Any use of my work's silicone (always water based) sprayed in proximity to linoleum floors results in break-neck slipperiness!! Okay -- promising so far. This stuff is awesome if you can apply it into a place that matters! That brings us to
303 Aerospace Protectant. This is a similar product to what I have used as far as I can tell.
I spray it in the long track that tambour runs along -- that works only partially. The bottle in the link above is a bit tall. I use a bottle that holds 4 oz. at most and is fairly short. Maybe look at Home Depot for smaller spray bottles. I close the tambour onto the thinnest part of my wrist and spray into the spiral uptake tracks of the tambour. That works every time! I can't say how bad the plastic-on-plastic would not glide until I invented my own trick this way. And the effect is durable and lasting -- what else could you want?
I really doubt it is your canvas backing causing the problem. We all take many weeks to tweak our trailers -- so ordering another product isn't too bad (when will it end?!?!).
Post again if you have problems.
(BTW -- LPS seems a little too light oil base for use near canvas, adhesives & plastics. I certainly would recommend the 303 first!)