Both work very well for the entire journey there and back. I use the first I get my hands on (typically scale armour) and upgrade it to +8. But if it’s plate armour, you might have to start using it before gaining the necessary strength, so be ready to spend more time and food on a few levels in the prison area.
For me specifically, if spoilers hurt a book, it probably wasn’t worth reading in the first place. I love when authors demonstrate mastery of language and narration, and no amount of spoilers can overshadow the direct experience of witnessing it enacted.