APM - as in Trevor Thom?
1. It isn't essential - CAP413 covers everything you need (the questions are from CAP413) and it is correct by definition.
2. No - if it isn't in CAP413, it isn't in the exam.
3. The 'old' Confuser had an RT exam, ask around at the school and somebody may have a copy - or somebody here probably does
4. I did the RT exam the day after my skills test, so it can be done. There should be no problems just turning up and doing the test.
HTH