It's about mortising the trigger group in the correct spot so that the sear is in the exact position within the "V" formed by the trigger levers. That I understand, but what's the best way to find the exact spot to begin mortising out the area that will ensure the sear and trigger levers are in the right alignment. I'm working with a blank slate, as it were, and using eyeballing in the procedure isn't a good method, IMHO. , I think I need measurements, and of course with those measurements I need points from which to measure. UNLESS someone has a superior method that insures a good and true sear engagement.