The latest typical circuit is can be found on NR code of practice sheet T28430 version 3, which is for a position1 and 4 PLJI. This shows a 110V AC circuit, with a common UECR (PC065) current proving relay, which picks if the current drawn is equivalent to 3 or more bulbs. The four Position 1 lights are driven over the 'A' Route UHR, Position 4 lights over the 'C' Route UHR and the pivot light over both UHRs in parallel. There is a common NX110 return which uses both UHRs in parallel for double cutting.
Additional - I forgot to add that this assumes the bulbs (if filament type) are driven from transformer/rectifiers (TJs) mounted in the PLJI units. If you have an older style of head with the bulbs directly fed, obviously you would use DC circuits of the right voltage, with a different specification of UECR. LED signals don't have the TJs.