I would recommend that you switch to an auction draft and wait until next year's draft to make it a keeper. Your owners can get a feel of how an auction draft works and what prices are being set. That way adjustments can be made in the salaries accordingly when you add the keeper component. That will also help you in deciding how much markup you should have based on the going rates of players in your league.
Making the jump from snake to auction draft is a pretty big leap, especially if owners are not used to that system. Keep it simple for them the first year