Mark,I would go with the 80.The plane you are getting is almost the same size as a hanger 9 cap with a 97 inch span.Most people are using the zdz 80 and it is a power house.You won't go wrong with the 80.You will have unlimited vertical.I had a extra with a zdz 60.(80 inch wing span)This plane weighed 15 lbs and was a rocket.Have fun, you will enjoy flying it.I have a hanger 9 cap with the 97 inch span with a zdz 120 twin for power.Latter