I think 4 3 3 is the best format. For example:
( 1 4 3 7) (9 8 6) (5 2 10)
( 6 9 2 4) (1 5 3) (8 7 10)
( 4 5 8 10) (6 2 1) (3 9 7)
( 6 4 10 3) (2 8 1) (7 5 9)
( 10 9 2 3) (8 1 4) (6 5 7)
( 7 10 6 1) (3 2 8) (9 4 5)
( 5 6 8 3) (4 7 2) (1 9 10)
Above players 3,4,6 & 10 have 4 foursomes and 3 threesomes (all 9 opponents exactly twice each), while the other 6 players have 2 foursomes and 5 threesomes (7 opponents twice each and 2 opponents only once).
Hope that helps.