Ah, i think we are talking around each other:
This is the Intake side, the Window rounded with Red is the Window for the stock Boost Port, The Green Circles show how it would have looked stock and not connected:
And this is the Exhaust side of the Piston, as i said, the Piston skirt is already shortened 7mm compared to a Stock Piston, and that window is at least 7mm High:
Where we come from we call both of those "Kolbenfenster" wich means "Piston Window" and we normaly do the second style on the Intake side if we don't want to port our cylinders. Mostly because it's easier to go back to stock if you only have a modded piston and don't need to find a Stock cylinder again.