Personally, if I was going there, I'd look at the Mesa Subway 215. Only 60 lbs, rated for 800 watts at 8 ohms, which is a great improvement over the 215's of yore. I have (and still use) an early 70's Sunn 215S which is way heavier than that (160 watts at 4 ohms, so really not a good comparison, but it is loud AF).
Having two 115's of course is a more flexible setup as well as easier to move. I doubt there's an appreciable difference in real-world sound if using 2 identical 115s.
I prefer having multiple cabs as opposed to one big one. There will be times where you only need 1. Why take 2?

