I recently bought 3 Exmark 21 Metro's. I really like them, but have noticed that I get a poor cut in a couple of conditions. I am cutting Bermuda and St. Augustine grasses with the mowers set on the 1 3/4" setting When the grass is thick, I get a beautiful cut with no missed grass sticking up. However, if the grass is thin, or if the Bermuda is tall, a lot of grass blades are left sticking up and I have to double or triple cut. The mowers have the blades on them that they came with, part number 42-1000. Is there another type of blade that might provide more lift and cut thin grass better. If so, what is the part number. Thanks.