I just f]got my SOT2 and I am a 07 FFL and looking at building a DIAS for some RD. I have tried to find out exactly what type of lower i need to mill out to support the DIAS. I know its a low shelf but what are those dimensions, I am assuming the pocket is a AR-15 and not M16. Also, I am assuming I need the M16 trigger and safety for a FA FCG correct?