I agree with the above post that you must try and maintain the 90 degree angle, but just make sure that you are paying attention to where your arrow would be exiting the animal. If you are 20 feet up and the animal is 15 yards out you want to try and get your entry and exit through the vitals. Try and do alot of practice from your stand with a deer shaped target and not just a plain target that way you will get to learn you angles.