CAT is one of the rare preamps which works in any system. There is no issues of synergy with it. I think if you compare a CJ preamp to the latest CAT ulimate MKII, it will have to be the ART. So, I think you should go with CAT. It will sound fuller, and yet more neutral then 16ls. In fact, I heard your amp with the CAT ultimate MKI and it was fantastic.
Good luck!
Good luck!