The branching ratio is not temperature dependent for DD fusion, its always 50-50 (its a standard model thing). Also its generally assumed that all the T produced is then burned at the rate its produced (about 10-100 times higher cross section) and this gives a 14MeV n (so half the neutrons have about 14MeV the other half about 2.5 MeV). However people generally differed on how much of the He3 is then burned. Often the approximation that no He3 is burnt at all.
I still don’t follow your numbers. Why do you triple your 13.3J? And why do you assume that Boron H yield is so much higher? Even at optimal temperature the cross section is many times lower than DD, or even DHe3.
