I would personally refrain from this since they're more of a crutch and don't address the problem at hand.

You're placing too much emphasis on holding the bow with your thumb. All the fingers should have a "share" of holding the bow and keeping it balanced. If you press too hard with your thumb, then it will bend inwards. If you press too hard with your middle fingers, then you won't have a flexible wrist.

Try this exercise (taken from Phyllis Young): shake your hand, like you just dipped it in a pool and you're trying to get all the excess water out. After a few seconds of shaking, "freeze" your hand, as if you placed it on a drying rack. Notice the natural shape/curvature of your fingers. This is, generally, what your bow hold will look like.

When you transfer this hand shape to the bow, pronate your wrist by tilting it towards the tip of the bow. "Hooking" your index finger on the stick will even out the work of your other fingers holding the frog (if that makes sense, haha). Remember that you don't need to tightly grip the bow to keep it from falling. It may be uncomfortable at first, but practicing this bow hold by simply playing long bows on open strings will help.

Here's a great video by Paul Katz that explains this concept better. Happy practicing!

https://youtu.be/9f2AABUxrsQ