You can clip the stinger off. If the ray is small use a pair of fingernail clippers, if it's large you can use a pair (clean) dykes. I've seen this done, it doesn't harm the fish in any way. i believe the stinger is made of similar substance as our fingernails. Any how it can be clipped and it will grow back.
Rays are one of the most difficult fish to keep, they require specific foods, as well as certain water conditions. Soft acidic water to be exact, and do not do very well for long in anything else.
i will say you have a taste for cool fish! Keep us informed on how it goes.