The specs for the 242 Hadcock I posted originally are wrong, the correct specs for the longer arm are listed below:
Mounting Hole Diameter 3/8" (15.87mm)
Overall Length 12.0" (304.8mm)
Height 1.70" - 3.5" (43mm - 90mm)
Pivot Stem Length to Top of Arm 3.4" (86.4mm)
Pivot to Stylus Point 9.6" (243.8mm)
Pivot To Centre of Turntable 8.9" (226.0mm)
Offset Angle 23°
Rear Overhang 2.40" (62mm) maximum
Headshell Mounting 0.50" (12.7mm) centres
Cartridge Mass 3 - 12g
Mounting Hole Diameter 3/8" (15.87mm)
Overall Length 12.0" (304.8mm)
Height 1.70" - 3.5" (43mm - 90mm)
Pivot Stem Length to Top of Arm 3.4" (86.4mm)
Pivot to Stylus Point 9.6" (243.8mm)
Pivot To Centre of Turntable 8.9" (226.0mm)
Offset Angle 23°
Rear Overhang 2.40" (62mm) maximum
Headshell Mounting 0.50" (12.7mm) centres
Cartridge Mass 3 - 12g