One thing I have found useful for main idea questions like question 8, where I do not have any strong idea what the main idea is and no answer sticks out to me, is to skip and do the other questions. Using this strategy the questions help build my understanding of the passage, in this case when I came back I quickly got the right answer.

There is not "experimental section" in the PTs on 7sage. When the LSAT was on paper it had 2 LR 1 LG 1 RC and then a fifth "experimental section". So 7Sage is not grading an experimental section.

My advice because this is a standardized test is that you should be taking the full length tests as this is how they were intended to be taken. When you check the flex box and do a 3 section test they estimate what your score would have been, basically by multiplying by 2 whatever you got wrong the LR section to account for the fact you only did one section. This means whatever score you get is not as accurate because the test is not only about your raw score it also has to do with your standing compared to other takers that day. When the test you were taking was actually administered it had 4 graded sections, that one LR you took could have been harder or easier than the one you did not.

Additionally, the August flex will be 4 sections and it is probably best to train for that reality having to do 4*35 minute sections. You will not know which section is experimental on test day either. Also 4th section could be any of LR, RC, or LG which is different than PTs but the best we have.

In short take the full PT it will give you a more accurate gauge of where you are scoring and will better train you for test day.