I've been in the lawn business for 7 years and now I'm getting into it a little more. I have a gravely 36inch pro 150 that is 3 years old and after looking at some of your photos of lawns that have been mowed with double blades it looks like I don't have to spend all that time bagging. My problem is that my local dealer tells me that the only way to run double blades is to buy the newer model of the gravely walk behind. My mower is in great shape and when I ordered it I spent the extra money for the highest h.p. available . If you can help it would be great. Also if any double blades will work on this mower please tell me where to buy them. Thanks so much.