Bill, the Parker butt plates yhat I've seen and used are as you say with a larger hole more on the radius of the heel. The newer ones that we're seeing now are lower ( more on the face of the plate) and the top and bottom screw are the same size. I personally like the newer style better but to each his own.
We are lucky that Glenn took this endevour on because the supply of skeleton butt plates was mighty thin. :o.
I like the thicker plate myself because as Dennis says you aren't going to crack the web with these. You also have lots of material to shape the edges into the shape you want.
Glenn knows that I have my order in for a couple of special plates when he gets the operation sorted out.
