Would anyone be willing to share their opinion about having tellers balance the vault cash? What checks and balances do you have if you use this option?

Ideally it should always be one teller, one CSR. If not, at the very least one of the tellers should be a supervisor - Dual Control is your friend.

I agree, dual control needs to be done. Our cash vaults are done with our vault teller and a CSR/Manager.

If your vault and your lockers can be set up for dual access/dual control - that's the best process.