i'm replacing the old dryer vent in the basement window, of coarse the plexiglass cracked when i tried to remove the old vent, pipe and caulk, so off to the hardware store i go. i knew nothing good would happen when the young guy used a big magic marker to mark the size. but anyways it's about 1/16" too big on one side and about 3/16" on the other. i know that's not a score and snap deal (from past experience). cutting the circle for the vent shouldn't be a big deal, but the 1/16" cut could be troublesome. any suggestions on what blade to use? thanks in advance, gramps