What was the initial question again?
Man Kevin I think I really want to come train in NOVA a bit in the summer with you guys.
never "receive" a strike but always dictate the terms of engagement
This is Aikido. From the other things you have said in the thread it sounds like you have everything else you need, you just need to put them together. Right now though I have a headache from reading you and Kevin's posts.
The only thing you have not mentioned in chatting so far is metsuke and proper control of ma ai.
Will see if I can drop some more answers later. In the meantime have a partner attack you with diagonal strikes (yokomen, gyakumen) to the head and thrusts (tsuki) to the stomach. Have him take one step to reach you with each strike (i.e. be just out of his striking range if he attempts to hit you without moving forward, we call it tegatana distance) and then return to his starting place and then repeat as quickly as possible. You should be able to use your peripheral vision and detect the direction of the strike and move in accordingly to get off line and "block" the attack by raising your arms towards his face. It is important that he does not telegraph his strikes and that he maintains his balance when striking, nor that he tells you which hand will be striking at which time, he should just strike however he feels like, given the above parameters.
If you can do the above without getting hit at all I would say that you have a good idea on how to control the terms of engagement with a strike already by using good metsuke. If this is the case then a grab should be less work. If not, I'll try to add some more stuff later.