The PST format is exactly like the sample that you can find on McK website, just twice as long and with slightly harder questions.
There are 3 separate cases for a total of 26 questions in 60min. For general tips:
https://www.mckinsey.com/careers/how_do_ ... guide.ashxAs far as time mamagement goes, you can follow the same strategies that you used/will use in the GMAT. The difference is that here you can skip back and forth with questions, so if you find time consuming questions, or you are unsure about a few answers, skip them and return to them later.
I would say that the test is rightfully administered at the beginning of the selection process as it is the easiest step (only your reasoning skills are tested, while in interviews you will have to think, talk, interact, and be an overall enjoyable person while knowing that everything you do or say is judged).
In my case they corrected the test immediately after it ended, called us one-by-one and told us yay or nay.
As far as hearing back, I submitted my resume and heard back the following day, so they definitely keep up with the applications submitted.