Depends on the application, but for low speed, low power applications, eg lathe change gear, model engine etc, I would opt for the cutter with the correct pressure angle. They are made to cut a range of tooth numbers so are not super-precision. I reckon you could get away with being one tooth out of range.

If you are making gears for the transmission of a 500 horsepower engine, you might need to be more fussy.

I did this with a Mod gear, to fix Son in Law’s bandsaw, at short notice.

The gear for the rise and fall of the upper guide was a sinter, loose on a shaft, with a flat to provide the drive. and had exploded.

Having put the jigsaw together, the OD and tooth count could just be worked out. But I had a 1.25 Mod cutter, but not a 1 Mod.

Making a replacement gear and shaft from the solid, and using the cutter to the recommended depth produced a visibly incorrect gear.

But using a depth of cut, reduced to 80% of the theoreticaly correct, (For that cutter) resulted in a gear which did not look too bad, and meshed well enough with the rack to do the job.

It was Chinese saw, where it was apparently impossible to make the guide adjusters concentric.

It was simple enough to make replacements that were!

So far as I know, the bodge is still functioning!

So it has to be worth a try, to see if a reduced depth of cut will give a theoretically incorrect but functional gear.  But not an expedientn that I would use where accuracy was required, such as changewheels.

For that, even for a one off, I would bite the bullet, and fork out the £30 for the proper cutter.

Howard