those stone tipped bits clog up with aluminum real fast so I don't use them.
the following is my tool of choice. You already have the shank with holding screw at the end of it that works with these. You can reach into ports better with these. If the disc is too wide then break off little sections of it all around it with your pliers (it don't matter that it's jagged).
Rotary Cutting Wheels $6 https://www.amazon.com/Dophee-Reinf...337309&sr=1-101&keywords=rotary+cutting+discs
this is what you will need to make the boost ports if you ever get a reed valve:
Solid Carbide Burr with Ball End (not for iron/steel) https://www.amazon.com/Cobra-Carbid...rd_wg=pXezN&psc=1&refRID=TK7DFD1CQG56T7W7CXD3
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