I finally caught my Research Breakthrough Latias!!!! I've been trying for so long!
What's crazy is, I caught it on the first Ultra Ball w/ a regular Razz Berry. o.O Well, I threw one and missed, but the first Ultra Ball that actually hit was an Excellent throw (possibly my first ever), and...shake, shake, shake, ding!
I named her Helios (in contrast to my Latios in Omega Ruby, Eos.)