Dimensions and Specs for a Marshall/Hiwatt Style 4x15 Square Cabinet

Hello, I'm getting a custom made 4x15 cabinet. I want it in the same style as the old 70's Marshall and Hiwatt 4x15 cabinets. I want it to be 16 or 8 ohms so that I'm able to run it with another cabinet, most likely one of my 4x12's. I also want it to at least be 300 or 400 watts so I can run it safely with both my 100 watt Marshall 1992 LEM and my Orange AD200B. For this project I need the dimensions of the old Marshall or Hiwatt 4x15 bass cabinets, I need speaker recommendations for the cabinet, and that's pretty much all I need. Thanks in advance.