Feo, regarding your mention of Roy Masters. I did some research on him a while back and found a lot more information about him through google/ youtube, and I'd like to provide that information here. The more information and facts that we have, the better choices we can make for ourselves, along with our experiences.
This article is about him and his meditation practice.
By the way this is out of sequence in the way I wanted to reply. I wanted my post to go way up above where you mentioned Masters, but instead it's down below.