WSO Consulting Materials + Video-Conference Interview

Hello

I have a 1st round scheduled in January. 3 Quick questions;

-How good are WSO's prep materials?

-My plan is to go through "Crack The Case" (I've been told that it teaches the frameworks quite well but is lacking when it comes to practice) and then "Case In Point" (I've been told that it is great for practice but is lacking in practice).

-How formally should I dress up for a video-conference interview? I am told that I will be doing cases as well in the 1st round.

Thanks!