When you talk about softies - zoas, xenias, clavularia, mushrooms, leathers - these are corals that spread across from where they are placed.
LPS depending on the type may grow outward flat, outward all around, or upward.
And it also depends on what scale you are talking about. To build a spaced scape in a small 15g cube which is going to limit not only the number of corals you have, but how much they can grow, is going to be different than trying to plan a spaced scape for 200g tank.
And if you don't have a tank you are upgrading from, where you know the inventory that needs a home, then a lot of your planning is hopeful. You just never know what you are going to find when you are ready to fill a tank with coral. You might come across something different than you had planned.
Build a rockscape that you like the shape and structure of. Then as you fill the tank with livestock space them according to the manner in which they grow/spread.
Dave B