Hajruden is supposedly giving Loki 3 minutes to explain. So, I'm guessing we'll get 3 chapters worth of backstory. One chapter per "minute". Probably 2 chapters for Harald's backstory and change of heart, and bit more with Loki's childhood, and then one more chapter detailing Harald's death. I doubt Oda's willing to show off what Shanks can do quite yet, so I think Loki v Shanks will be completely off-screened.
....I could be VERY wrong about that. We could get a LOT more. But, I still think Oda probably wants to keep this relatively short.
Although, I am halfway expecting Oda to take his "yearly" month-long break pretty soon. So, even if it is only 3 chapters, it might take us two months to actually see it all.