I've got the 9" Lazer drill bit on it. I was expecting heavier resistance, but it was infact very smooth and effortless. It drilled as fast as the old 8 inch Strikelite blades, maybe faster. The slight increased hole size doesn't appear as excessive as a 10 inch but it merely only looks slightly bigger than the 8 inche hole.
If anyone else is thinking of drill bit upgrading their Strikelite. It works just fine with the 9 inch Lazer drill bit.