In case anyone else here needs this, I succeeded in patching smartmontools 5.41 to read the 710 series smart counters.
They're basically the same as the 320 so the patch essentially involves copying the 320 definition and changing the device id.
Since I only have 100G drives, I may not have the device ID correct for all sizes (guessed that they were the same except for the size).
diff -ru ../smartmontools-5.41.orig/drivedb.h ./drivedb.h
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