With LPS and SPS, you'll come to a point when dosing elements is essential. Do you have an idea which method you want to use? with my 180g, I find that 2 part works but consumption rates have gone up substantially as the tank filled in and matured. With that said, some monti's will take up a lot of space. If you place them too high, you run the risk of shading out corals mounted below. encrusting monti's might be a good option to mitigate that issue. I've always been a fan of acans and chalices in the lower to mid range of tank. for the top half, I would consider birdsnest, stylos, digitatas, and starter acros.