I'm going to try it with a butterflied whole roasting chicken. At the supermarket, I couldn't believe the difference in cost. For about 7.5 lbs, the chicken was about $7, and the turkey breast over $27. AND the chicken was "minimally processed" while the turkey had that cheap broth/salt water they like to inject.
Or maybe I'll do two casserole dishes, one with parts that take longer. Then I can time them separately.