You can edit all your league settings via the Edit Link that is included in your confirmation email that you received after registering your league.
League commissioners can also email leagues@sportsvault.net (or submit a Help Center ticket) with their updated payout structure and their league page will updated automatically within a couple hours.
All you need to do is include Payouts: in the email message and send it from your registered email address. If you commission more than one league, please include the league name of the payout structure you are updating.