Whatever the supposed length, the confirmation shall be for one heptad.
Daniel 9:27 King James Version
27 And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate.
In the middle of the 'seven' He (Yeshua) will put an end to sacrifice and offering. (It is finished John 19:30).
Now for some fun, that is determining the 'middle of the week'.
The Hebrew year begins on Rosh Hashanah so to go to the middle of a week (shmita cycle) count three and a half from the shmita and come to Pesach (Passover) to arrive at the middle.
How do you determine a shmita year? Multiply by seven. 7 x 541 = 3787.
Now count 3 and a half (Hebrew) years from Rosh Hashanah 3787 and you fall into Pesach 3790, the middle of a week. The Passover of The crucifixion
Yeshua's ministry lasted three and a half years, Daniel 9:7 is split between the Messiah and the ruler (anti-Christ)
Lots more at:
666, the number of a man
http://www.freerepublic.com/focus/f-chat/3572025/posts