How fast corals grow depends totally on the individual coral and the setup/parameters of the tank they are in.

 

As for rock placement try to keep room in the back for the water to continue to flow circling the tank. You don't have to keep all the rock off the back wall but make sure there is room for the water to circulate behind the rock. This will help eliminate dead zones and aid the gyre motion of the water. Create as many caves and openings as you can. As the current strikes the rocks and moves through the openings and caves it will create diverse flow patterns. When you add fish it will also create interesting areas for them to move through and use for getting away from the occasional aggressor.

 

While the tank is relatively empty is the best time to play around with various aquascaping ideas and maximizing the flow through the tank. Once you add fish and corals it becomes harder to make changes and more stressful on the livestock.

 

Keep the pics coming as you dial in the tank.

 

I am also using this method in my 55 Gallon Frag system. In that tank I create a gyre that goes around the tank like a whirlpool instead of top to bottom and the frags have responded nicely to the increased flow.

 

I should mention that turbulence is also important, strictly laminar flow or flow all going in the same direction is not preferred. Turbulence is created in the gyre as the currents impact the rock and other stationary parts of the reef. That is why having multiple caves, and openings in the rock is important. The water needs to be diverted as it travels around the tank thus creating turbulence even though the power heads are all pushing water in the same direction.

 

Here is a good article on flow and the reason for using the Gyre

 

http://coralmagazine.coverleaf.com/coral/20100304#pg43 - http://coralmagazine.coverleaf.com/coral/20100304#pg43

You can make the gyre go either horizontal or vertical the only thing that matters is that the water all be going the same direction. In my Nano which is a cube I have the water going in a vertical gyre or across the top down the front and back across the gravel. In my 55 I use a horizontal gyre which is more like a whirlpool.

 

Looking at your rock stack I can't tell if there is any room behind the rock. This isn't absolutely necessary but if you can keep at least portions of the rock off the back wall it will allow the water to circulate behind the rock better. As far as pointing the power-heads I would position the one on the right so that it is just above the top of your rock pointed slightly upward (maybe so that if you drew a line through the output to the left corner the line would touch the surface). On the right side I would place the power head about 1/2 way down on the back wall close to the right corner and pointed toward the front glass (maybe just Little to the left as well. This will allow the water to flow straight across the back wall then across the right side and across the front back to the left power head.

 

Again you may have to play with it to get the best circulation you can. In my frag tank I am not so concerned with how it looks so I put one power-head on the left rear corner pointing across the back and one on the right front corner pointing across the front.

 

Hope this helps.

Flame angel is great but is hit and miss as far as it nipping corals.

Dwarf lion, very cool, but might eat up everything you put in for a cuc.

Clowns are fun to watch and easy to keep.