All I can say is that it works for me and I have definitely stress tested it over the last 19 years.
I have made 3 of the big freighters and stripped one of the big canoes twice (23 ft freighters that are beach and surf launched), once because I wanted and see what, if anything, was happening to the fabric and to change colour; and after I had passed it on to the scouts, it had accumulated a lot of sand and gravel underneath the fabric, in both cases the fabric and cover was in nearly new shape and as strong as when it was put on.
I have had a highway guard rail go though the side of the oldest big canoe (my fault) with very limited tear to the fabric but 4 ft of 1 1/2x 1 1/4 ash inwale and 1 1/2 x 1/2 outwale plus 8 ribs and planking required some urgent attention (the 10 day 250 mile trip continued on the next day with a cheap and nasty repair)
I have given the routine that seems to work in my hands whether the canoe is 9, 12, 16, 18 or 23ft .
The rational is that weight is important and I am pushing my capacity to lift and move these boats particularly the big freighters. Having one part of my body forecasting changes in the weather is one thing, but a chorus is downright disconcerting. Using epoxy as a paint and a graphite epoxy paint/filler hardens the surface and seems to have made up for any lack of abrasion resistance as compared to new canvas. Twenty years of being left outside seems to have caught up to me and my canvas canoes faster than I want, I don't like to admit it but it is more than once over, so not having redo something I 'just did' (even if it is 15 or 20 years ago) seems to be a better and better idea. I know canvas can last a long time if it is kept dry and protected but my canoes don't get pampered that way.
I didn't realize it at first but one of the main reasons a canvas canoe gains weight so rapidly when dumped is that the under surface of the canvas wicks up the moisture. Another feature is the dacron is more stable than canvas and doesn't crack and buckle the way older canvas canoes do hence no need to do the repainting for waterproofing.
A selection of my stress tests are not all my stupidity, but my wife may have a different take on this. The list is not endless but it seems long enough. I must add that there are others who have participated as well in the stress testing.
One of my big freighters was dumped in a storm and surf (my friends son) the occupants picked up in response to parachute flares (don't expect those ****ty little things to work), but the boat and gear later pulled out of the beach (literally buried in the beach and surf) by several boats and only had paint scratches, The motor and gear was a different story.
I do know that canvas would not (and had not in my misspent youth) have survived some of the things I have done to the layered dacron fabric.
The 30-40% weight saving is real as is the durability.