I am not sure on the yield for pit beef, but it will be more than 50%. You number for the pulled pork is fine. If you feel comfortable with those numbers, go for it. All the leftovers will freeze for a later date.
Team: Pyle's BBQ; Yoder YS640; Good-One "Trail Boss" 60T; Weber Kettle w/rotisserie ring; Big A$$ Rotisserie; Weber OTS; New Braunfels offset smoker; Weber Smokey Mountain; Chargriller Akorn.
Saddles BBQ Bistro