The number of sizes available is relative to the number of different sizes we offer across all of our products.
For example, you might have a 1:1 with 3 in prints sizes and 4 in canvas sizes in which all but there are 2 sizes that overlap. The total is 5 different sizes across the board.
There is a tolerance of 10%. This means that if there is a square picture but off by a couple pixels, it would bring up all the square products that would be within the 10% tolerance. It would bring up all the square and all the products within that boundary.