I have converted several Homelites and they have very low vibration, even with the flywheels. I think the 25cc would be just right for the 82" AT6. The weight up front would be helpful. If you can get the bigger carb for it, do it. It will increase performance considerably. Carrprecision has them and Wackerengines might still have them at $20. Your Homelite 25 probably has a small hole just above the exhaust port. If you plug it (I use a set screw) it will increase compression.

Jim