i too agree that is a little unecessarily complicated…personally i would worry a little less about flexion vs extension etc…but maybe theres a reason u are doing this that i dont understand and that maybe u could elaborate on and teach me something new…
i am also against the 1RM on the sit-up, something about that just doesnt seem like a good idea, i mean is the sit-up going to be your max-effort lift? again maybe there is some reason for this that im not seeing…y would u want to go for a 1RM on a sit-up of all exercises?