As for the wine, do give it a try and it probably won't take long for you to know how it reacts. For most, it's personal preference to go with a sweeter wine or dry. My personal preference is dry wine. It's something you sip slowly and it relaxes you (at least it does for me). If I have sweeter wine (which I don't prefer) it goes down more like a soda and I don't think you want that, especially something that's really fruity like sangria. You aren't doing this to quench your thirst, it's just something to relax you. And you can pour as little as you like, or just enough to take the edge off. Well, you can think of it as for medicinal purposes! A lot of people do. It's true, alcohol does make a lot of people pee more urgently and copiously. A can of beer would do that for me, for sure! Maybe that's why I haven't had any for who knows how long. It's like coffee, I've just gotten out of the habit. Maybe the bladder is letting me know who's the boss!
But a little bit of drier wine taken slowly may be worth trying.