No problem using a .23mV Kansui with a PH-6. The PH-6 has far more gain versus any of the older SP preamps you mention.
If the SP series will handle .2mV then any of the modern ARC phono preamps, i.e. PH-5, PH-6, PH-7, PH-8, etc., will work fine.
I know I have owned the SP-10, SP-14, PH-5, PH-6. The PH series are much, much better with LOMC(.2mV) versus any of the SP series. The SP-20 will have similar gain to the PH-6.
If the SP series will handle .2mV then any of the modern ARC phono preamps, i.e. PH-5, PH-6, PH-7, PH-8, etc., will work fine.
I know I have owned the SP-10, SP-14, PH-5, PH-6. The PH series are much, much better with LOMC(.2mV) versus any of the SP series. The SP-20 will have similar gain to the PH-6.