LSAT Flex and Study Process

Two questions here:

I can see that 7Sage has an option for testing that allows for simulating the LSAT Flex with only three sections. Considering the test is back to having an experimental section, should I be prep testing the LSAT Flex three sections or continuing doing the regular four sections? Only issue I can see is that yes, I'd be getting the same stamina on four sections with normal prep test, but it would always be an extra LR section. Thoughts?

Secondly, does moving to three equal sections on the LSAT Flex (no extra LR) change my study habits? I do decent at LR for the score I am shooting for, but do significantly worse on RC and LG. Should I jump around in core curriculum to meet my needs?

Background for second question: For the first three months of studying I had been using another text besides 7Sage, but just became frustrated toward the end of the book because I did not have any guidance when I got stuck on concepts. All this to say, I know I am too late to get the entire core curriculum and appropriate number of prep tests before my October test.