Are you saying to add one of those other brands with a RSL 12s or just buy 2 of the other brands to start with and so t get a RSL 12s at all.Sorry just wasn’t sure what you was saying.
Your post read to me like you were gonna add the emo even after getting a second RSL. If that were the case, I’m still recommending not getting the emo. But instead something from Rythmik, PSA, monolith, etc.
imo you’ll want matching subs. So four 12s would be very nice in there. If you have a penchant for BASS, then a pair of fv18 from Rythmik, or even a pair of 21’s from PSA, OR a 24” fromRBH or funk. The rabbit hole is deep my friend!
Edit: or better yet, some DIY devastators…
At the end of the day it depends on goals. And how loud and low you can spend!