Well first of all, the input impedance of your Plinius amp is 47K Ohms which should be benign to even the weakest tube preamps. In my opinion, with your Plinius amp I would just go for a Vac Renaissance Mk3 & upgrade the tubes. Kevin Hayes has a nice collection of NOS tubes in his own 'Vac store' & is always happy to provide his wealth of knowledge. I think the Vac would be a good match sound-wise & imho, anything more is overkill and I would just buy a killer integrated instead like a Vitus SIA-025, Gryphon Diablo 300 or JRDG Daemon.