Re: 7A16A high frequency compensation.
to check my PG506 I used 3S1/3T77A pair, connected with a 20 cm GR874 airline. Measured a risetime of 750 ps and aberrations as per service manual. So I did prefer touch nothing. :-)
R436 is the one pointed by the green arrow in my photo and it's O.K.
The unknown R is the one pointed to by the red arrow. See https://groups.io/g/TekScopes/photo/262075/3