You can check my math.
For 70d with a .75 oz coating finished weight of aprox 2.75 oz per
yard squared. HH after wear tested of 3515 mm
Allowing for 5 " sidewalls and a hem.
8.5X6.5 equals 55.25 square feet or 6.1 square yards.
6.1 X 2.75 oz equals 16.8 ounces or roughly 1 lb.
With a heavier coating, say 1.5 oz you would add
6.1 X .75 equals 4.6 ounces for a total with the thickest coating
of 21.4 ounces. Richard's HH after wear testing was also 3515
If you used some 70d with a .5 oz silicone coating,
which has the HH after wear testing of 3445, the total weight
would run about 15.25 oz.