All I can tell you is on the 71C and 72 C models, pressure tests are done by unscrewing the temp sender and installing the gauge.
FWIW, These are the manual's pressure specs for those 2 model series:
Transmission Pressure Specifications
Engine RPM
Neutral Gear PSI (kPa): 600rpm: min 115 (793)/max 135 (931)
Forward Gear PSI (kPa) : 250rpm: min 70 (483) /max [blank]
" 600rpm: min 115 (793)/max 140 (965)
" 2000rpm: min 125 (862)/max 160 (1103)
" 3000rpm: min 135 (931)/max 180 (1241)
Reverse Gear PSI (kPa): 250rpm: min 70 (483)/ [blank]
" 600rpm: min 120 (487)/max 140 (965)
" 2000rpm: min 125 (862)/max 160 (1103)
" 3000rpm: min [blank]/max [blank]
You might call Velvet Drive to see if the 5000 series has similar specs, and if different get them from VD.
http://www.velvetdrive.com/