Am I crazy for trying to manage crappie in a pond this size?

IMO yes by that method unless you want to do a lot of work with high risk of failure. If you want large crappie leave in the LMB as they are the only effective predators you have on small crappie. Ken is right on the CC. When small CC will help with the BC but not much when big.

Here is the archive on Crappie

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=92447#Post92447