I don't own one but the folks who do seem to like them. I know very little about the device.
I'd imagine you could use nic salts in them, there aren't really "special" devices devoted to nic salts, they function just the same as regular freebase nicotine. Whether you can "handle" 45 mg/ml nic salts in that device, is going to depend on you, how much you vape, how nicotine tolerant you are, and how much vapor the device delivers to you per puff. My (hazy) understanding of the Sourin Drop indicates to me that it's not a particularly powerful device (but I freely admit I could be wrong on that) and you may well do just fine with that high nic in your device. However, if it is too strong, it should be a simple enough matter to dilute down your nic salt
juice and/or purchase lower strength nic salt juice, but I see nothing wrong with trying it in that device to see how you do.
Be aware of nicotine overload symptoms as you try it: things like dizziness, fatigue, hiccups, headache, nausea, yawning, etc., and if that happens, don't vape as much, or if you need to vape that much, lower your nicotine percentage.
Best of luck, and welcome to ECF, hope you enjoy your stay here.
Anna