The Sdei Chemed (Klalei HaPoskim 10:2) delineates the order of authority and reverse chronology as follows:

 1. Shu"t HaRashba
 2. Torat HaBayit / Avodat HaKodesh / Piskei Challah / Shaar HaMayim
 3. Chiddushei HaRashba

He does bring a Pri Megadim who considers the possibility that certain Teshuvot were written prior to the Torat HaBayit and leaves it beTzarich Iyun.