The AU-300LC is versatile enough
As long as you don't need more output, you don't need a different SUT.
While in standard form, it's a perfect match for the DL-103 (higher impedance than 103R).
You can tune it by loading it's secondaries with resistors.
110kOhm when using the DL-301II.
33kOhm when using the DL-103R. (don't worry about signal loss, the 103R has more output than the manual states)
Technics SL-1200 Mk2 recapped / MN bearing / Funk Firm Platter / Denon 103R / Lundahl LL1933
Thorens TD 126 MkIII / SME Series III / Ortofon SME 30H // AT-OC9ML/II / Lundahl LL1681
Thorens TD 160 / TP16 / Stanton 681SE