In such a scenario, the reserve rate can be calculated by looking at deposits to the deposit address, transfers to and from the storage address (probably held in cold storage,) and withdrawals from a withdrawal address to find the bank's liabilities and on-hand reserves. A fourth address could be used as a gateway within the bank for managing loans (with each account being a separate address known only to the bank and borrower,) whereas transfers to and from anything but the storage, deposit, or withdrawal accounts would be the bank's loan assets.

Given that address construction, all you need to do then is to calculate liabilities (what's held on account,) and weigh it against the calculated reserves to find the reserve rate, then you can also check that against the loans that you can also calculate from the loan address. Using this full system, the bank's average interest rates are known publicly, both for loans and deposits, in addition to having a publicly known reserve rate.

That would be an extremely good financial institution for an economy to have.