[bolger] boom on a poor-setting sprit?

Unless you really want to add a boom, try cutting a spritsail with some
deliberate, calculated shape. You can use RLaine's Sailcut program,
which can be downloaded for free. The sailcut program allows you to
dimension the sail, including amount and location of camber, for any
width of panel you wish. The program gives xy offsets to describe the
panels that you can cut out and glue or sew together. I used it for a 65
sf jib for my chebacco. The home-made sail sets well.
Cheers;
Fraser Howell