[Amps] FL-2277 B & FL-2100 Z

[on4kj]

Hello folks,

I am trying to refurbish an old FL-2277 B Sommerkamp .
Unfortunately  chematic and manuel I dispose of is a FL-2100 Z.
The look is very similar, but they are not. 
Some minor details on the chematic . 
I have some questions:

a) What is the best version  2277B or 2100 Z? 

b) FL2277 B ALC circuit, why do they pick up the HF sig on the grid of a 572B instead of the cathode , or the common power input on the cathode ( filament ) ? Or could this be a ham introduced error ?

c) The grid current limiter resistors 33 E 3 w . One of these resistors has been modified by a 2 x 22 E serial comb. !!

d ) Is it a common practice to use one of the power suply bleeder resistors as a voltage divider, -40V ( calculated value ) used in the grid bias circuit ?

My first impession, the wiring and construction of this Amp is not an example of professional skill..... 

Who shouts please.

Jos on4kj