What I particularly like about Kirk's approach is that it allows for some customization. Additionally, his members section has a program of instruction which includes detailed information on setup and drills to ingrain the feeling of getting to a good impact position efficiently. Another instruction who seems really good is Chandler Rusk (CMR Golf Team on YT) who does remote video instruction. Rusk used to be Graves' top instructor before striking out on his own.  He also recommends JMX grips.