zoom, these are going to lay down a base for growing before growing upwards, so you need to leave plenty of room for that growth. For them to grow into one another, one is going to live and the less aggressive one is going to die.
I place them according to what lighting and flow requirements they need.
I would leave more than 6" inbetween them though. With fast growth they'll get together even quicker.
As my Rose BTA take over my right side of my tank i was force to get everything out of that side.
So i redone the left side for just SPS I never had any small frags before, is no way to get any SPS frags or any colonies in South Jersey, i got all my form different vendors and let me tell you most of the colors are not what you see in there web page pictures.
My space is limited so i like to put is many as possibole without to need to trim them every month.I saw pictures of MDM tank and the frags are very close to each other and i like that but i don't need to have to trim them all the time.May just let them grow in to each other you think is this possible?
Thanks for the help.