Prudent smoker:
were you able to probe the frozen breasts or did you stick them with an instant probe to check the IT (or did you just "wing it" :

)?
is there a need to increase the amount of wood? I ask b/c it seems frozen meat wouldn't take smoke (although I have no idea at what temp it would begin absorbing smoke...).
were the breasts brined before they were frozen or were they straight from the store to the smoker? were you able to put a rub on them while they were frozen or did you apply after?
I apologize for the multiple questions, but throwing frozen meat into the SI and pulling out a cooked meal is extremely enticing to me. I appreciate any data you can throw my way.