Thank you! I've been saying this for years! The wood is as dry as it's going to get when the instrument is made.
Nitro is fairly soft which makes it easy to rub out. It also burns into the last coat so you don't get witness lines if you sand through a coat. These are why people like it. But it takes like a month to fully cure. Spay can lacquer is sometimes softer because it's made to flow better from a spray can.
I've used both nitro and acrylic (auto body) lacquer from spray cans with much success.
Builders started using poly finishes because they dry faster (especially the UV cured stuff) and create less air pollution. But then you have to spray them on thick so you won't have witness lines.
Another myth we might as well kill here is that the finish on your solid body bass does not change the tone. A thin nitro finish does not sound better or "organic" (stupid word to use for a tone). Glue lines also do not stop vibrations and this whole idea of vibration transference between parts is wrong.
If all the energy from your strings was transferred into the body, like everyone thinks is a good idea, then your bass would have zero sustain and sound like a banjo!
But the body has too much mass to vibrate like that. And a very thin later of paint has no affect on any of this.