A lot of people use an allen key carefully ground square so its a good fit in the slot,
Other than that its very easy to make one of the type recently posted on site by simply measureing the lock, you know the important sizes so the rest are merely cosmetic and comfort,
Make it so it fits the lock then design it so it fits the fingers, try it out in cereal packet card first until you get the design right and then post the template up here
