Awesome! Thanks Ewo & F-Clef-Jef.
I had tried All Parts and couldn't find anything but feeble small banjo tuners, forgot to try Stew Mac.
I just checked the string guages on Hagstrom's webpage for the HB-8 and they are good to go – the Steinberger tuner's maximum string guage is .060
Hagstrom's 8-string guages:
2nd-G (Octave) *.015
4th-D (Octave) *.025
6th-A (Octave) *.040
8th-E (Octave) *.055
Gotta go start practicing Tom Petersson riffs.