I love field maintenance discussions. We are in the process of building a bull pen at our high school. We have a net that is 12' high and 20'ft wide for the back stop. We dug out the pitching and catching area about 5" deep. We have back filled this with a really good red clay. Also the the cathcer area and the pitching area is outlined with some landscape timbers. Bermuda gross is everywhere else.
We gave the pitcher enough room behind the pitching rubber for her walk through drills. We had enough room for 52' feet I think,from the plate to the back of the pitching area. I installed 2 of the large 6"x6" pitching rubbers, the throw down ones with the 3 spikes will not last any time with teenagers wearing spikes. The big ones last forever. I have also layed a 2'wide x 6' long x 1'' thick piece of rubber in front of each pitching rubber. These are under ground about 3". This keeps those J shaped craters from forming. "Well not as bad."
I have about a 1/2" of slope so the water will run off. I am in the process of getting new infield material for this winter, and I will top dress the bull pen with the same material.
Both sides of the net will be used for Tee work, we will be able to have 4 girls at a time doing Tee work.