This is usually where Dick Hanson says something like, "Our planes have extremely low wing loading because we learned a long time ago that 15oz. loading is the absolute most you would want."

I'll say that the smaller the plane the lower the number needs to be and 26-28oz sounds OK for a 72" plane. It's easier to build bigger because once you get into 35% and up it's easier to keep the weight managable. You don't see a lot of smaller scale planes that are good at 3D, you usualy have to have a funfly with really big wings compared to an Extra or Edge to have good wing loading. 72" AND scale is a real in between size and will do aerobatics but is hardly ever a really good 3D plane.