There is a bounty on providing an rpc command for UTXO management (https://github.com/gridcoin-community/Gridcoin-Research/issues/1173). We need to focus more energy on getting MRC done, which is the complement to CBR. Many people shouldn't have to worry about their UTXOs too much anyway for a reasonable staking efficiency.

A really simple rule of thumb is just to split any UTXO you have that is much bigger than 2000 GRC. That should be more than adequate...