There is no way to know until after the fact, basically when it comes to hyperinflation you never know how high it will be as governments for the most part once they realize they have destroyed the economy to that point for the most part hide that information, depending on what kind of living standards you want to have, the number of people that depend on you or how much you want to take advantage of the situation the amount of bitcoin you need will vary wildly.

Just to give an example while it is known that during the US Great Depression many people lost their jobs and were desperate, a very little known fact is that more millionaires were created during this time than at any other moment before during the history of the US, why? Because the few that had gold and other hard assets used them to buy stuff for cheap from the ones that were desperate for money and when things went back to some sort of normality they now had a huge number of assets.