minimum would be 8. getting through 3rd round on loser side is your loggerhead - they you're simply at the mercy of the slowest player(s). i think southaven rec has 9 (icbw) which we have made work. me and steve have had a couple "spiritied debates" on how you could have everyone play at least one on the first day, and winners play two - which polulates you bracket for approximate start times on day 2. but it would require a modified 3-2-3 format (which means everyone plays at least two days instead of 1/4 the field being out in the first evening after traveling across the country....). pros and cons to each. but steve is admamtly against it - so a moot point it is....no matter what format, gotta play 5th/6th games on day 2.