@twangy57 I have learned some things from your series of recent threads even after being reactivated in this hobby for the last 20 years after a long break. You can get a lot of valuable information here once you learn how to apply the appropriate filters.
At one point I had convinced myself that a tube preamplifier and high damping factor solid state amplifier was the way to go. I ran into the same impedance matching issue you have been describing when shopping, and I ultimately went in a different direction. Based on everything I have read here, I think the CJ amp you purchased will sound very good in your system, and look forward to your comments on whether it meets your needs.
Folks have suggested you adjust or upgrade your cabling. I would hold off on that until you are satisfied that you have the right gear, or are at least comfortable with the sound of the McIntosh pre, CJ amp and Focus speakers. I agree that power cords can make a big difference, but given that your pre is essentially vintage, it is probably more valuable in resale unaltered. A great 20 amp c19 power cord may unleash even more of the beast in your new 350, but something tells me it would rock pretty hard with whatever comes with it from the factory. For my current system, I did not realize some of the soundstage characteristics and capabilities until I upgraded from budget speaker cables. The Focus 360’s deserve good cables and you should be rewarded immediately for upgrading there once your amp arrives. You can start another thread for advice on cables when you get around to that but be prepared to buckle up and watch some sparks fly.
And yes, a decent budget phono pre will pay great dividends. Some here have mentioned Rega and Schiit. I have both a Schiit Mani and ProJect phono preamps and prefer the ProJect. YMMV.
kn