Correct sizing of pond liner for above ground pond

I need some help from people with experience. We are going to use cinderblocks 8 by 8 by 16 to build a pond. The inside dimensions of the pond will by 4 ft wide by 11.333 feet long and 32 inch high. What we planned on doing is getting the pond liner 6 feet long than the width and length to have 4 inches to lay over the top of the cinderblocks before putting a "top" block that is 4 x 4x16 and using mortar and the block to hold the liner in place. We wanted to use EDPM liner to withstand the sun we get here in NC. So is this feasible? Of is it not going to work and we need a larger liner. Right now I'm figuring a 10 by 20 liner. All comments welcome even if people do not agree.