Hi TCB1
I'm certain that you will get some other methods/opinions on here, but heres what I do.
How much material are you adding? What the drainage of the current infield? If your going to spwend all this money on a good infield mix and diamond pro, make certain that your starting with the best base that you can.
First of all, turn over your existing surface and remove any weeds, overgrowth, stones etc. that exist. This will allow the overlayer that your adding to bind with the lower layer.
Same thing when you get to adding the diamond pro....after you get the surface up to the height you want, loosen the top couple of inches and work the diamond pro into the entire top layer. Don't just lay it on top of the surface, you will have a much more playable surface if you have the calcined clay mixed in. It will take more product that way, but you will be much more satisfied with the result over a longer period of time because as the surface blows away, and it does, there will still be D pro in the surface to keep it dry and true.
Hope this helps, Mike