That's what I do. I tend to favor old master copies.
I rip them to both FLAC and MP3. The former is for listening at home, the latter for mobile scenarios. I store everything on the Linux server at home, and share via UPnP. VPN into the home network gives me access from anywhere.
Foobar2000 is my preferred player on Windows, BubbleUPNP on Android.
> kit built tube amp
What's the distortion on that thing?
The vast majority of tube kit schematics are very old tech, stuff that engineers from the 1930s would recognize. Their THD (coefficient of total harmonic distortion) is very high. What is known as "tube sound" is basically just huge THD, along with a specific distribution of energy across the harmonic orders.
It's fun as a hobby, and for the satisfaction of building stuff on your own, but even the simplest schematics built on modern principles vastly outperform these things by essentially all metrics.
Some tube amps are built specifically for low THD, but unfortunately they are rare. When in doubt, use solid state.
> homemade single driver speakers
I used to build everything myself back in the day. Speakers and amps was just part of it. Also did automation, radio frequency (I'm a licensed HAM radio operator), digital circuits from logic gates to DAC/ADC to systems with microprocessors to small computers. It's a small miracle I didn't actually go into electrical engineering.
You really need multiple drivers and likely a subwoofer also, to cover the whole audible spectrum.
I’m not worried about the whole spectrum as I only listen to classical on it, primarily string quartets. The speakers are folded horns, so bass response is reasonable.
Anything like Dream Theater or Iron Maiden is in the car. Would definitely be solid state with a subwoofer for that.