Not necessarily but....
As noted previously, once you get the impedance ratios in compliance between the pre and amp, exchanging tubes, rolling them, will allow you to affect the sound without degrading the signal.
How much warmth you infuse into the music is almost entirely up to you. The brand of tube line stage is as well another factor.
Older CJs, as I understand it, produce a more mellow, romantic sound. Albeit, these are all subjective accounts being listed here. For my money, Id offer that the BAT VK5i I once owned when outfitted with the right tubes could be as warm and rich as any Id heard save for SET outfits. Fully balanced, and a killer line stage, but used eight signal tubes and two output tubes. So a mite spensive to fully retube frequently with NOS tubes..
As good as is the build quality and ease of operation, and its exceptionally low output impedance, and now its inordinately low cost to buy, Id look into buying a Thor line stage, or line stage w/phono. Formerly a $10K preamp, and one of the top preamps made in the world, you can get one lately for next to nothing. The MK II or serial number above 1000 would be my suggestion.
Bare bones, purist approach. SE. 4 inputs, 2 outputs. Separate power supply. Esthetically, a real eye catcher. Sound? Quick. Fast. Dynamic. Sweet. Organic. Realistic. No matter what amp follows it downstream, it will sound better. I guarantee it. 4 tubes. 2x12ATs; 2x12AXs. 400 ohm output impd.
Ive heard no late model tube preamps, Cary, CJ, or BAT, which sound euphonic. Overtly warm or romantic. Due only to the tube compliment inside of them, you have the opportunity to slide the warm meter in that direction. Were you to start dabbling with NOS tubes.
Another note to think about is the power consumption or needs of the speakers, and their impedance curves so you may more properly fit an amp to them, as this segment of the line is IMHO more critical than is that between the pre and amp (s).
I think your idea of tube + SS for panels is a very good one
and pretty popular too. Cruise the virtual systems for more pointers and ask more questions on amps for them.
Good luck.