I did PT 60s and I think they are comparative harder than 50s and 40s. Maybe it is because LSAC changed some styles. But the fundamentals are the same. Premise, conclusion, get the support, get the flaw, attack it or bridge it!
Also anything un-timed after learning the fundamentals is useless. The time constraint makes you think, and behave differently, you must get used to it so that it becomes second nature.