CAD systems like Fusion360 and Onshape are free for non-commercial use and about as hard to use as MS Paint.
Measure the bolt holes, the physical space you have to fit it in, and how far out you want it to protrude, then draw it out.
Somebody’s sure to have made a science of dog spikes, but you can really make the spikes however you want. This is a common replacement part for a widely available saw, so I’m guessing you’re doing custom anyway.
I’ve had bad experiences with the spline tool, though. It gets output as thousands of tiny lines and curves. Essentially your machine has to cut a ton of little things. Much easier to use a similar arc, and that’s probably what they do from the factory in the design phase anyway.