Since the decision has been made I'll just say this last rock set up looks really nice.
Was just wondering about the stone, hate to be a downer but would anything like sandstone change anything about your water? Actually I was going to buy a nice piece of rock yesterday and the guy told me not to because it was sandstone. I hope not because I like your rock very much, looks super in there.
I'm not 100% such if it's sandstone. From what I read sandstone may raise ph some, just have to test it. Also I've read that you can do a vinegar test, if the it frizzes on the rock, don't use. If not, it'll be safe, but always best to test the water.
Currently getting ready to do a test on a piece in a bucket, planning to allow it to set for day, test the water, refill, test, etc..