Well you might have got all your bark's got to give. 3 quarter g isn't a top range yield but it does roughly correspond to the much touted 0.6% you see around... 12.65 ph sounds a little low to me for a STB; might be worth your while to try and up that a number, will take quite a bit of lye though. Weigh your desire for that extra % against cost/availability of your chems and the time it will tkae you