To be honest I don't think the peek-a-boo stancewould be very good. With your front leg extended like that your asking for a kickboxer to go for your inside thigh. Or a decent grappler to shoot for your leg. Plus "head down, hands up" doesn't give you the ability to sprawl as fast as you would using orthodox. And you'd be put on your back instantly.
Peek a boo is perfect for a short fighter trying to work his way inside against a taller opponent in boxing, but in MMA it proves problematic. MMA features few sustained punching exchanges and so a more orthodox guard with a slightly extended lead hand would be my preference.
I thought the Pee-a-boo’s lead foot was extended less than the orthodox stance. Closer to that of a wrestling or Thai stance that the orthodox.
Not the way I was taught, I was always told that you want to be able to move as fast as possible to get inside the defense of whomever you are fighting.