Ken Lambert has done one with a Homelite 25cc, and he says it's perfect. Ryobi should have the same power or a touch more. I think Ken used the magneto ignition, and had to add a couple of ounces of lead to the tail. I'm doing one for my next project, (with the Homelite), and I'm using electronic ignition so I don't think I'll have to use any weight for balance.

BTW, we are talking about the biggest stick right? The Ultra Lite Stick 120?

Good luck,
AV8TOR