Line by line? No.
A lot of MCs do 8x8. Game used to do it a lot you can hear it on documentary although he doesnt do it anymore, but it used to be 8,8 or 4, 12 or something like that.
It is always best to record the verse in ONE take, but 8 and 8 is acceptable. The main thing is, if you cant perform the verse in one go, how are you ever going to rap it live?