Cutting the breast in 1/2 should make it fit OK on the lower shelf.
I have done that for different reasons and it coos just fine.
Just a thought.
"Flirtin' with Disaster" BBQ Team (RETIRED)
FBA and KCBS Cook and Judge.
Former owner of a WSM, a Smokey Joe, a Charbroil Commercial gasser (junk), the legendary "StudeDera", a Fast Eddy PG500, and Sherman.
Now cooking with a Yoder YS640
Proud Pellet guy cooking on real wood.