[Radioroslyn]

<Also, the schematic doesn't really make the distinction between the floating ground components vs chassis ground.>

It does there's no ground symbol.

The circuit before mentioned isn't really floating it's just grounded (@#59) thru 165 ohms worth of resistors. It subtracts some B+ thru these resistors and makes negative voltage. This negative voltage in turn is used to bias the grids of the 41's the output stage, the 7C6 grid in the 1st audio stage, and the 1232 suppressor grid in the rf amplifier. These grids need to be at a negative voltage to help mange the electron flow within the tube. In most cases without this negative bias too many electrons will flow from the cathode to the plate causing excessive current and can damage the tube or parts connected to it. Things like output transformers, chokes, field coils, and resistor can be at risk.
Point is that some folks think that the negative side of a filter capacitor always is connected to the chassis. Not so much!

Now the post war ac/dc sets those have a floating B- but that a different story for another day....