Re: Towers or Horizons?
If you go with 2 more Horizons, do you have stands/rack/furniture/something else you'd place them on so tweeter is at ear height approximately?
Otherwise, option 2. FWIW, I have the ELX Towers & ELX Horizon for my front stage.
In either case, you can move the Lunas to surround (if need surround), use them elsewhere (e.g computer), or sell them.
As to sound of option 1 vs. 2, my guess is no difference but Dave's input would be definitive.
* LG OLED65E6P, BenqHT2050A
* Anthem AVM90, Rogue ST100, VTV Pascal 7 ch
* Sierra Towers/Horizon (all ELX RAAL), S2EXv2 surrounds, HTM200SEx4 heights, Rythmik E15HPx2
* VPI Classic 1+ (VTA & Fatboy Gimbal), PE Eagle/RR, VAS NOVA, Soundsmith Paua, Manley Chinook, Bob's Devices SUT, SugarCube 1 mini
* Oppo 203 & 103D, EverSolo DMP-A6
* miniDSP Flex, Audiosensibility & Blue Jeans cables, Symposium & Isoacoustics, GIK
* For RDJ: Anthem MRX720, Sierra LX, Luna Duo v2 center, CXNv2, TBD