I sold my 16LS mkI a couple months ago after several years of thoroughly enjoyable ownership. Your 7308s should work quite well. I enjoyed tube rolling the 16LS and had no sense that it was hard on tubes. I used mostly Amperex 7308 and 6DJ8s, the latter being a bit more harmonically rich in the upper mids and highs, the former a bit more articulated at the bottom. Mine did well plugged into an original Hydra.
The 16 is a real treat - I call it a 'preamp with soul'. Used in the $3k-4k range it is a solid value that is hard to beat, imo. Soundstaging is what you'd expect for a preamp of this caliber, with nicely layered depth, and width occasionally ranging one-to-two feet beyond my speaker boundaries. Instruments and voices stay in place. Throwing a decent soundstage is something most equipment in this price range does pretty well nowadays.
The real strength of the 16, imo, is its overall coherence - it plays well within itself and has no glaring faults. Very good but not superb timing, yet still with plenty of snap and vitality. Tonally a bit on the warm side, but much more toward the neutral than CJ preamps that came before it. With the 16LS (and ART), I feel CJ took a big step closer toward neutrality (yet there's no mistaking them for ARC gear.) Nice dynamic range especially toward the low end - highs are not quite as extended as the low-end, but have plenty of air. Tube choice will impact the highs, imo, so there's something to play with. With the caveat that I have not heard the new CT5, the 16 is, imo, the best sub-$10k preamp CJ has made.
