Just for another data point, I am using the 8bitdo SN30pro+ wirelessly, and for me it worked as folks have described it is supposed to. Select goes to the menu and I can navigate it, with the a button (right) confirming and the b button (down) going backwards, a la a Japanese PS1 or an SNES controller. Oddly enough it mapped the buttons perfectly except that A and B and X and Y were mapped literally, which makes them backwards for how they should be for a Saturn pad. I was able to manually remap them without a problem, though. Aside from that, the emulator mapped how I would've wanted it - Z is L1 and C is R2, L is L2 and R is R2.
I previously had the libretro core installed, and in my initial testing so far I am pleased to see that the standalone is definitely running most games much better (Panzer Dragoon especially I noticed). That said, there are a surprising number of games that crash entirely or freeze in standalone for me that are running well in retroarch. Maybe that will change in time as the emulator improves, but for now I am keeping both installed. I'm praying for lightgun support eventually - can't wait to get my sinden going on these games.
Cheers to all the hard work that got this running, it's awesome!