Does anyone know where to find a direct comparison of the sound of these two guitars? I don't care about a tremolo bridge, and theoretically the 245 should sound richer with shorter scale, thicker wood, and mahogany neck so I'm leaning toward the 245. The only thing that makes me want the custom is the coil splitting to get the occasional strat sound. Or has anyone compared each one's sound.
I see this is an older post, but thought my recent experiences might be relevant to some in this, the future.
Seems we frequently don't directly answer querstions because we want to tell our own story. Well, I'm not imune from that disease, but my experience may shed a little light toward your problem.
Below are my 3 PRS SE STANDARDS, the 24, the 245, and the Santana. The 24 has a 25" scale, the 245 and Santana are 24.5".
All 3 are P.T. Wildwood, Indonesian guitars mfg in 2017, sold as 2018. Each feel very different, plays very different, and, originally, sounded very different.
(Aside: I have a bias FOR the P.T.Wildwood Indonesian guitars. After buying and returning 3 of the newer Cor-Tek guitars I'm pretty sour on them, 1 new SE Custom 24, I new SE Zach Meyers, 1 used Standard 245)
It's an interesting question, which is why I ended up getting all 3. The 245 seemed to have a darker tone, more midrangey. The Santana was next darkest but had a lighter quality, and the 24 was very, very interestingly full bodied and clear....it can handle distortion well through my Katana MKII 50 watt and, in fact, gave what seemed to me to be the best sound, clean or dirty, of either the 245 or the Santana. I liked the pickups in the 24 so well that I purchased 2 more sets on Reverb and put them in the 245 and the Santana. But don't listen to me...I have this stupid idea that a guitar should have some definition, and I can't stand metal or totally fuzzed out sound. If that's your thing, then the SE 85/15 S pickups in the Standard 24 are probably not going to make you happpy. For me, they changed the muddier, mushier pickups of the 245 and Santana into really sonically superior instruments. True, they all sound more similar now, though the 245 still has a decidedly darker countenance, and the Santana is lighter and bouncier than the 245. But it's easy for me to see why they put the 85/15 S in the Standard 24...it's the perfect fit for that guitar. I am amused by people saying the 24 is more "strat-like"...why is that? because it has a 25" scale? I find it is nothing like a strat...it's like...a...a...PRS SE Standard 24. That's why I bought it. If I want a strat, I'll buy a strat. To my ear, the coil splits have little in common with the "Strat" sound. Sure, you get single coilish sound. And it's great. I love it...adds a whole new dimension to the sound. But the same is true of the other 2 PRSs that I've put the 85/15 S pickups in....coil split and all. They don't "sound like a strat". I would say the Standard 24 is quickly becoming my favorite guitar, though I really have to admit I am smitten by each and their respective characters. Every time I put one back on the wall and pick up the other one it's like coming home to a different woman...(did I say just that?...hope my wife never logs on to the PRS forums...)...they just feel..."right".
So, as others have advised you, you need to try them if you can. See which one feels and sound the best in person. The 245 is decidedly much heavier than the 24 or the featherweight Santana and that weight ads to its tonal character. It's darker with less highs, more mids, more bottom. The 24 is clear and crisp, some have called these "hi-fi" pickups though I wouldn't go that far.They weigh in at 9k-ish for the bridge and 8k-ish for the neck.
That is my experience. Asking for advice about how a guitar sounds is an exercise in futility...everyone will have a different experience and a different way of describing it. From what I've read in these forums, some people really like the sound of the 24 and its pickups and some people really don't like them....although I've read LOTS of "opinionoids" by some folks who haven't ever really played or owned one, let alone 3 PRS SE STANDARD guitars. Yes, I am a shameless addict, and PRS is my current addiction....so many quitars...so little time.... Good luck with your quest!