I think we may be on to something here. Any player can challenge a position on Mondays and Wednesdays. Each player get 10 GB or FBs and 10 swings of front toss. Coaches judge each swing/hit and fielding attempt (1 to 10 on paper), tally it up and announce the winner. Monday's winners plays Tuesday and Wednesday's winners plays Thursday. As iron sharpens iron, so one person sharpens another.
I like it. My DD dominated front-toss competitions in her day. Unfortunately, live pitching turned her swing back into a pumpkin.