You're a braver man than I if you even think it's tackle-able.
I voted "change it" but it occurs to me, how much harder is it to go through it, and then create a *new* topic, using those old messages as the fodder for creation?
Some sort of a drag-and-drop copy thing that preserved the 50 page doc but also copied the relevant ones into a new format would be another way to approach it IF it's technically possible.
If it's too hard to do that then have fun reorganizing
I'm sure there's good info in the thread but I can't use it as it is.