Mugen MBX5T
Someone else with an MBX5T please post up arm measurements, my calipers aren't too accurate (cheapy digital ones from Harbor Freight).
Inner hinge pin diameter = 3.840mm (.1512")
Inner side, outer width (D) = 54mm (2.125")
Inner side, inner width (C) = N/A By Arm Design
Outer hinge pin diameter = 2.667mm (.105")
Outer side, outer width (B) = 44.1325mm (1.737")
Outer side, inner width (A) = 26.67mm (1.05")