I redid the Blaupunkt radio in my 63 FHC and found some very good resources in the process. Here is my thread link: Original Blaupunkt 32471 radio Help
And the link to Radio Museum: http://radiomuseum.org/ Where I got wiring info as well as schematics.
And our own Michael Frank as a collection of info: Michael_FrankPatron
"Sigh! I do all this work and nobody notices:
https://www.coolcatcorp.com/Radios/Radios.html "
Michael’s website is a fountain of information.
And a link to the fellow I found most knowledgeable … and helpful … of replacing and wiring the speakers on these old radios and where I found the proper, high quality speakers perfectly matched to my old radio: Greg Thompson at: http://turnswitch.com/
And finally, one of J-L’s own who knows more about speakers and their parameters than I could hope to learn in my lifetime: @Robert_Wilkinson
I hope some of this you’ll find useful.