I've had minimal success in the past, but I guess it could
have been the seed lot. Thanks.

Dan

Sounds like par for the course.

The Floridata website says ...
"In cultivation, African tuliptrees often are grown from seed, but
seed production is erratic. New specimens can be started from tip
cuttings, root cuttings, or suckers. "

Are you really trying to grow a tree this big ?
http://www.floridata.com/ref/S/images/spath_ca1.jpg