Hi Till E., Nice concept. I just don't know how to go about it. Do you suggest maintaining the depth at the base, increasing the height by 3 1/2" and adjusting the depth on top to 6 1/4" and this will give you a 22 1/2 degree slope? Do you start the slope at the very bottom of the front baffle? I am very interested in this design for my 2Pis. Edwin