Zander, I have a concern about this, and Steve, please don't take this as knocking an otherwise very practical suggestion.
You have an LP12. Fifty quid will get it serviced and in tune from a dealer, and I can't believe it will do anything other than blow the �375 Stanton all-in-one out of the water sonically. Surely the purpose of the venture is to reconnect with all that good music you have on vinyl? I'm sure the LP12 will do a better job of that than the Stanton. There can't be that much issue with phono stages...I feel that you are worrying unnecessarily. I've used a Musical Fidelity XLPS and XLPv3 with a 562(vanilla, v2 and v3), and the voltage has never needed anything other than the 2.2V sensitivity setting, which corresponds to the MP221. Cartridges have been Audiotechnica AT-OC5 (IIRC) and Ortofon MC25FL.
Your 5ks would have retailed at the thick end of �4000 when new. They are capable musical performers. If you want hifi sound from your vinyl into the DSPs, the Stanton will undoubtedly do that. If you want music though, stick with the LP12.
Just my tuppence worth...
George
LP12/RB300/MC25/XLPv3