for 4.5"+ it is a #3. For smaller hinges, it is a #2 who further clarified the #3 as 12 side and the #2 as a 10 side.
The correct answer however is T25. The 12/24 machine and #12 wood screw from PBB for the Full Mortise Hinges 4B81 x 5 x 4-1/2 x NRP x TMS x 652 - PBB when packaged with Pin Torx screws is a T25 Pin Torx driver as seen here:
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