The fitting outside radius is rp in Fig. D-1 of B31.1 Appendix D. If omitted in Caesar II this defaults to the branch outside radius, which is conservative except in Fig. D-1(d) which is the same. The branch SIF (for reduced intersections) is inversely proportional to the value of rp, so as this is increased the SIF will decrease. There is no crotch radius for reinforced fabricated tees. The Pad thickness is only used in the Run pipe flexibility characteristic calculation so does not affect the branch SIFs.