What is the minimum amount of room needed between the m80 and the screen?

Also, will it be an issue if part of the bottom of the speaker where the port is is behind the bottom part of the screen where the border to the screen is. Hence having a partially hard surface covering 1/4 to 1/2 of the port 3-4 inches away?

In regards to boundary for base, if I did invert these suckers, they would almost be on the ceiling, and it would put the tweets ear level. I'm really having a hard time as this is being built seeing that the tweets will be 18-24 inches above my head if I keep them right side up. I really need to snap some pics for everyone to see.