[Arran]

The cathode pins of the 7B7 tubes are also connected to B-, all the way back to the power switch. Pins 1,2,7,8 are used on the 35Z3, pins 3,4,5,6 are unused and could be tie points for anything, there is no pilot lamp tap on a 35Z3 tube, the set parallels the pilot lamp with a series dropping resistor, part #48, which is a 53 ohm job connected between the hot side of the power line and the plate of the 35Z3, an 89 ohm resistor connects between the plate pin of the 35Z3 and one of the filament pins of the 35Z3.
There are only two filter capacitors in this set from what I see, the third on the replacement may be parallel connected with one of the other filters or it may be connected as a cathode capacitor on the 35A5 tube. Though this set did not have a cathode capacitor from the factory it was a common modification to improve the bass response of the power output stage.
Regards
Arran