What PTs in the 70s and 80s should I watch out for

Hi! I'm taking the November flex and have PTs 78-89 for practicing up until then - spacing out 2 per week pretty much. Any word of advice for which are harder/hardest? Or is there a discussion on which PTs the flex is resembling the most?

I've studied starting in 60s, taking them in order starting from 2010.

I heard Pts in the 80s are difficult compared to others, so I'm nervous to even dive in and kill my confidence..

LMK! xx