I shoot with both eyes open, no peep. I use 3 anchor points, kisser and anchor sight. I hardly look at the anchor sight anymore, only when I am shooting out past 60 yards, I can shoot hanging tennis balls out to 80 yards. I use to shoot with a peep, but found it annoying when the string would twist and tweak the peep.
Both eyes open and a peep, wouldn't shoot any other way, sight picture is double of what it would be if you keep one open and that peep makes sure that you are where you need to be. May take you a bit of getting used to but it will pay off in the end!
Works every time until it doesnt. Then to top it off the tube slaps you in the face. Can you tell this happened to me.
Not quite as bad as a D-loop letting go and punching yourself in the face but it still stings for a longggggggggg time.
I try to do both eyes open but if I hold too long I can notice my left eye (RH shooter) will start to focus too much. To counter that I actually squint but don't close my left eye while looking through my peep with my right.
If you can learn to shoot with both eyes open you will have a hard time trying to shoot with one eye closed or at least I do. I feel way more comfortable with both open.
You couldn't pay me to ever go back to a tube peep. Get zapped in the eye once and say it works every time LOL .