I would also get a second 12s. It will be much easier to integrate with the first one and overall will be better. I personally like larger, or multiple woofers for a variety of reasons(mine are 12”, and even my surrounds have dual 5.25). One reason being smaller woofers can’t do the upper bass and midrange regions with any real impact. You can raise the XO, but IME you end up with a tubby sound, and the midband just doesn’t come through like it should. Of course every room, system and user preference will be different. IMO, I would be missing out by using those mains despite the fact that they sound very good. Mileage is different for everyone though. This could be a case of FOMO, but it could also be MO, lol.