Fortunately the issue of requiring the alignment instructions for a specific FM or AM radio is solved by another method:
The "alignment instructions" of nearly every typical radio of that era, with the circuit configuration you have, is spelled out very very clearly (in English no less) by the manufacturers of the generators intended to do the alignment at the time.
They show how & where the generator and scope should be connected, what padding resistors are required etc.
For example, if you look in the service manual for the Philips PM5326 generator (A generator that I have often recommended) I'm pretty sure it clearly shows you how to do the FM alignment, including the ratio detector. (I will look at the manual tonight)
So if you got a copy of that manual (and preferably the generator too) you are already 98% there. It pays to read the manuals of good test instruments, many of the answers to your concerns will be found there.
The manual is on line, have a look at manual pages 20 to 30:
http://bee.mif.pg.gda.pl/ciasteczkow.../Pm5326%20.pdf