Horsehead,
All of the available hawks will be close in size, not exactly the same. Most of the handles you will find on the market will be a little oversized and should fit into any of the hawks. You may find it to be a little larger than the eye on your hawk which will allow you to drive it home and create a good snug fit. After I mount a new handle I often drop it, head and all, into a bucket of water which will swell the handle into the hawk very tightly. Be sure to oil the head first if you soak it. I do have some straight grain pre shaped handles and one curley maple blank
Mark