This is a dovetail saw handle I designed for an old gents saw I had. It should fit most saw plates of about the same size, but you might need to drill new holes for the fasteners.
There's a template to mark the hole positions and the angle the plate needs to be cut at to fit into the slot on the handle.
Use the saw blade itself to cut away the supports in the slot, as that's more of a guide to keep cut parallel with the handle.

I used fusion 360 to design the model. I can include that file or a step file for anyone that's interested.