Welcome! You are speaking my language here, happy to give some insight. I've got a '62 SFIII and an MIJ//USA Casino that are my two main electrics at the moment, and I've handled a lot of vintage 330s.
The white top DeArmonds in my Starfire (and just 50s/60s DeArmond 2000s in general) have a really full, round but articulate tone. These paired with the hollowbody give you really great sort of "electrified acoustic" response/tone that is woody but bright. They can get into brash tele territory on the bridge pickup, and on the neck can get jazzy while also retaining some clarity. The middle position is my favorite to use for fingerstyle. I've played old duo jets with these pickups and they're incredible - they provide the same super clear, pristine, articulate clean sounds. Overdriven, they can get a bit brash and aggressive sounding, but that works well depending on what kind of music you're playing and how much you're riding the vol/tone controls on your guitar/what pedals and amp you are using.
The ES-330/Casino thing is definitely different, but not that far off. I find that the middle position with P90s is a really nice and articulate clean sound, but it doesn't give me as much of that "electrified acoustic" feel or sound. I find that the P90s definitely make it more of an "electric" guitar, if that makes sense. The neck pickup is super wooly, bassy, and warm - maybe sort of like the DeArmond neck but with a blanket draped over top. The bridge p90 is classic rock and roll - I used it for a gig sitting in on guitar this past spring with a friend's band and basically lived on the bridge position the entire time to be able to sit in the mix properly. On it's own at home, I can't say that I find it useful as it feels a bit brittle as a clean sound, but live it's a really great tone, especially with a bit of overdrive. The P90s generally seem to love overdrive pedals and more pleasingly overdrive an amp than the DeArmonds. The warm, wooliness of those pickups works super well in that context as you don't get as much of the harshness of other pickups when your signal clips, and this is pretty nice when you want feedback as you can kind of ride that hollowbody resonance without killing your ears with high end.
One way it has been put to me in the past is that the DeArmonds require a bit more precision when it comes to touch to sound good, since they're so pristine, whereas with P90s you can be a bit more sloppy with technique (especially with overdrive) as your sound is enveloped in warmth and gooey wooly goodness.
All of this is dependent on your technique, amplifier, and individual guitar of course, but hopefully you find this helpful. I'm a mostly fingerstyle guy that plays almost exclusively with nails, so that for sure affects my perception of these guitars.
I just remembered I have recent demos of both that I put up, here you go:
Last thing I'll say, as told to me by the great David Bromberg while discussing guitars recently - "I wouldn't kick either one out of the case".
