[Mondial]

As to the reversal of the green wires, it makes no difference. Although reversing them will invert the absolute phase 180 degrees, the phase relationship between the push pull grids will remain unchanged.

Did you check the RF tube screen voltage as you vary the volume control?

Can you get a full 90 V there with the volume control at max? If you can get at least 90 V at the screens, then all the associated resistors in the volume control circuit are ok. Their exact value is less important than their voltage division ratio, which should provide the proper 90 volts or so to the screens at full volume.

I first thought that the 12K resistor only fed the screen of the detector tube, but after magnifying the schematic it looks like it is in parallel with the volume pot. If this resistor has reduced in value to 8.2K, it will compress the control range of the volume pot, so this may be part of the problem. Add a 3.9 K resistor in series with one end of the existing 12K and see if the volume action is improved.

Changing the .025 uF coupling caps may help the volume problem because if they are leaking and causing excessive current draw of the output tubes, it will load the supply and alter the bias conditions of all the tubes. I would change these first before considering any other possible.causes