[35Z5]

This partial schematic shows how heaters should be wired, this is totally independent of any other circuitry in radio. Has no idea there is a pin 6 on 6SQ7. With this circuit can't be more than 300ma through heaters. The Red feed should be connected to pins 3 & 5 of 25Z6 while Blue is return(negative side of filter caps). That circuit should be drawing roughly 70-80 ma.

Yes it'd make more sense if switch was before Red feed in upper leg of circuit, but it'll work same either way. The safety minded often rewire the switch in that position and install a polarized cord. 

BTW I forgot about 20 ohm dilal lamp shunt resistor, along with the 40 ohm, values are fine.