The point isn't if ink overflow is going to happen shortly after the ink pad counter reaches full. We know by experience that it doesn't until much later, but logic says that it will happen eventually, probably before the first year, if the OP prints the number of copies that he intends to do beforehand.
Do do you realize how much ink is needed for 10.000 13x19" full color prints on canvas ?
This media requires more ink that photo paper and 13x19" is roughly 2.5 bigger in area than A4 or letter size. We know too that cleaning cycles aren't triggered only by the time elapsed since the last cleaning but also when a certain amount of ink has been ejected by the nozzles. Even if automatic cleaning cycles are minimized by replacing all the carts at once, a considerable volume of ink will go down the pads on a regular basis, one way or another.