I know

that Jasta is pronounced like yasta and both "a" are pronounced like in "spa".
Syd, your
rhymes with faster, plaster and blaster is pretty close if you try to ignore the final "r".
Wolff is volf and Schafer would be
Schar (as in scar)-fer but the German pilot's name is
Schäfer and that is
Shai-fer!
The German "a" is like hut or spa and the "ä" is like the English bad.
"au" is cow
"äu" is toy
"e" is like felt or day
"eu" is toy
"i" is fit or feel
"ei" is fine, Mike!!
"ie" is feel!! Last two just the other way like in English. And it is Kriegsmarine and not Kreigsmarine, kreegs... not krygs...
"o" is top or goal but minimise the a
"oo" is long o like boat but again minimise the a
"ö" nearest would be sir, fur
"u" is put or rude
"ü" is similar to ... nothing, it is the French
sur but sir and fur will be close enough.
Yugd-gesh-varder is pretty good! Well, if the first vowel is like spa!
Konsonants are less of a problem, "w" is v, "z" is ts like in hats but the German "ch"...

it is like the Spanish "j". Just imagine someone is being strangled or snoring...
Save the link Bruno has given, it works pretty well!