yup, too even.
there is no magic formula that i know of, just trial and error and pay attention to how well players are shooting (and thier TOs as well) as you adjust the distro.
I generally like to have my top scorers around 18-20. sometimes as low as 16 or 15, but that would indicate a team with a lot of scorers.
Some folks use a rule of thumb that no player should be higher than 20 distro... and i like that in general. i would only go over 20 once i have a really good feel for things and have a definite reason (such as "the kid continues to shoot a great percentage as i increase distro and i dont have many scorers so i would really like him to get more touches" or "somehting about this particular matchup tells me this kid could light it up", etc.
one other thing that i allways try to do is pay attention to each player's shooting percentage as the season wears on and keep tweaking the distro up (very slowly,,,1 or 2 points at a time) for the good shooters and keep tweaking it down for the poorer scorers.