Check the Internet! Effect of Batting Order on Runs Scored. That guy recommends ordering players by on-base average in descending order, so the players who get on base more often hit more. I don't think the setup for your league would change this conclusion much.

The reality is, lineup order has surprisingly little effect on the total number of runs scored.

Note for non baseball fans, on-base average is obtained by dividing the number of times a player reaches base through hit, walk or being hit by pitch, by his number of plate appearances.

Here's another interesting link: Protection - Hit or Myth?.