Here is a typical mouth openning, just enough to let a shaving through. The blade angle on this batch is 52 1/2 degrees so it is designed to plane without tearout on most woods.
Here is a picture with the wedge installed. You can see it is curved which provides two points of contact on the flat underside of the cross pin, this is an important detail which makes sure the blade is held very tightly in place. You'll also notice I've chosen a different wood for the wedge which has much more spring than the very dense Kingwood. This spring is also important in ensuring a tight fitting wedge. The wood I've used here is Lacewood (London Plane) but Oak, Ash and Walnut are all good alternatives.