Vuth...:
No, it may sound fine with the 50 ohm fixed load, but then you will not be able to experiment with other loads (you did mention "full potential").
Considering how positively the phono section of your amp is reviewed, and that it has enough gain, I would give it a go (and I'm not a gambler).
Perhaps it's possible to increase the load via cable choice and/or another method if you wish to experiment?
Anyone want to chime in on this?
DeKay