Although im sure you can get cad drawings, I have a whole stack of 1.25 gears here in case you need a real life measurement.
It never hurts to test things in real life. Here is the web calculator. Only needs a few input parameters. And because it user defined pin diameters, maybe you have something with suitable diameter kicking around (there are min/max limits but you are not bound by the recommended pin with 4 oddball decimal places). If its an odd tooth gear, as discussed, just ensure the pins are positioned at their closest position to 180 opposed.
Gear Measurement over Pins Calculator | Evolvent Design
Make sure your gear is the right size by checking its dimension over pins or wires. This measurement over pins calculator works on module and diametric pitch gears of all sizes
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