[MrFixr55]

Really nice workmanship!!! Top of the chassis looks great.

Sorry about the long winded explanation, a bad habit of mine.  I was technical team leader on my job and was responsible for training people as well as dealing with the stuff others could not fix.

300VAC on the 80 plates sounds low, but if the radio works and the transformer is not hearting up, it may be OK.  42s are rated for 250V on the plates, and considering that the other tubes hooked by transformer to the same B+ Point, I think that you may be OK.  Other voltages sound OK.

I looked at the Schematic from the Philco Library and the following N/A one:
Philco Radio & Television Corp.: 91

Of the 3 or 4 N/A schematics, at least this one has voltages listed.  The 250V supply is about 25 or so percent low   Yes, the 2700 Ohm resistor instead of 3200 Ohm will put a bigger load on the power supply but not by much.  In these things, 20% is acceptable.  The plate (to center tap?) voltage of 300 V vs the listed 310 V is only about 3% off.

Sorry, I have been calling the wirewound unit a Candohm.  It is not.  The chokes look to be correct unless glommed a long time ago from another Philco.

Yes, changing the cathode bias of a tetrode definitely changes the gain of the tube.  In fact, this is done on several TRF sets and sets using Biased detectors.

Gotta run to Choir practice, keep us posted.

Run the radio, for a while, unplug and feel test the transformer and choke.  Unlike older sets like a 20, the 80 and 42s will get hot so be careful.