I now tested Bench 2019 with my 8 Titan X (1 maxwell, 1 Xp, and 6 Pascal), and got 1265.
And...someone got 1298 with 2x 2070 Ti RTX... (in mode "RTX-On")
To me the short and sweet is this....
You will have the same render time as you see now for your scenes, but instead of at the benchmark resolution, you will have that at 1080p.
In other words, if you want to, with a non-RTX card, ball-park simulate what it would be like to have all your cards at RTX speed for a 1080p-ish scene, set resolution at benchmark's 933 x 560.
You can essentially cut the resolution of your scene in half. Whatever speed you get, that is ballpark your card would get on your scene with RTX!!!!