Looking to drill my 65G acrylic tank on the upper back left and right. I want to keep the holes as far apart as I can. How far from the top am I looking to drill? I would like to keep the water level as high as i can since this is a semi closed top. Would having the elbow from drain a inch from the top be to high? Looks like the center of bulkhead would be 3-4" from the top.