While you might not be able to get 3200 RAM working now, it's probable you'll be able to get it to work soon enough. Samsung B-die, single-rank is the best bet for high speed.
Also, if you really want high capacity you can get 2667 double-rank in 2x16GB sticks as Ryzen does quite well with double-rank RAM in that it's faster than equivalent single-rank (but you can't get it to clock as high).
I ended up with 2x8 GB Corsair Vengeance 3200 as it was $135 (or $125. The red was cheapest.) I didn't feel like spending $180+ for faster G.Skill RAM (CAS 14 vs. 16)