I use the thumb and forefinger method, since I have a tendency to torque the bow otherwise. The other fingers touch the bow handle, but they're just along for the ride.
To make this work, I find a place where I can pull the weight of the bow back against the web between my thumb and forefinger, so that the bow doesn't need any other support to be held at full draw. In other words, I can open my hand at full draw and the bow won't go anywhere. The only purpose of the thumb and forefinger hold is to keep the bow from flying out of my hand when I shoot it.
I never ask for a high grip; I don't think I've ever shot a bow that has one. I just ask for whatever the normal grip is that the bowyer makes. I don't shoot with a high grip like Fred Asbell does. Some of the weight of the bow rests on the meaty part of my hand between my thumb and lifeline, but I make sure the force vector of the bow is centered at the bottom of the V between my thumb and forefinger.
Rod Jenkins taught me that. He shoots where it is hot and muggy, and doesn't use anything to improve his grip on the bow when his hand gets slick with sweat.
Not all bows are amenable to being gripped like that. If I get one that's not, it doesn't stay on my rack very long.