Symbolic logic means: Putting logic into symbols. That doesn't make it a different type of logic. It is still a logic test...and the logical explanations (before they are symbolized) apply to all logical systems where you can deduce an answer (like LR with quantifiers REQUIRE).

I think that you're making the LSAT more complicated than it needs to be. I'm not masochistic enough to go back through my prep material, given that I'm perfectly satisfied with the score I got, but I know that a number of the questions about relationships about the size of sets.

I also know that most of these questions can be symbolized with sets rather than symbolic logic, and

*most* means greater than half in that context.

Take set A. Most of the members of A have some quality B. In this case, P(B|A) > .5

I know that symbolic logic is cool, and I definitely think that it can be helpful on the LSAT, but don't lose sight of the forest for the trees...