The contract needs the following 4 inputs:
Account Owner (this will be the private key that controls the contract account)
Annual Rate (we divide this number by 12 and multiple by contract's ETH balance to calculate withdrawal amount). Lets use 1%. So every month 0.08333% of the contract's ETH will be sent to the withdrawal address.
Blocks between withdrawal (we can count blocks to approximately represent months, we want the contract to make one withdrawal per month). Let's use 183,902 as the number of blocks between withdrawals. Or please tell me if you have a better method of keeping track of time within a contract.
Withdrawal account (this is the address the monthly withdrawals are sent to).
Please let me know if I can be more specific on any of these items.
Thanks and I look forward to working with you!
-Ben