I have been wanting to attempt a WILD, but I am a little worried about SP, although i have been getting more curious and less worried lately, but i would like some questions answered before i go and try to WILD

What is the worst scenario of SP?

What is the most common scenario of SP?

What is the best scenario of SP?

Does SP cause REM to occur earlier or something similar to cause you to enter a dream?

How long does SP last for?

Thanks in advance for any answers, it should help to clear alot of my worries if i know a little more about it