Thanks for the response!
The group moved on tohttps://groups.io/g/UCSDPascal
because the new Yahoo owner (Verizon?) decided to remove all user content in 2019.
A spidered image (from 2019) can be downloaded herehttp://pascal.hansotten.com/uploads/ucsd/yahoo/files.zip
(with meta info)
Two utilites looked good - but failed on the skewed images - so i needed additional steps (see post above)
a) PSYSREAD (Delphi, with PAS source) complete with a nice GUI (Windows only?)
[included in the file dump from 2019]
b) command line utilites from Jefferson Computer Museum ('bu.exe' = UCSD burst files to disk)
[must be obtained from web site ?]