That will work fine but if you have an outcropping in the rock (or can create one) were the coral can be placed so it is shaded, it will do much the same. As time passes, slowly move the coral outward into the light every few days which will allow it to slowly adjust. It will not be all that practical to keep adjusting the lights every time you add a new coral. Not to mention annoying
I a higher light demanding coral, it can then be moved upward an inch or so every few days until the right placement is achieved. At 31" to the substraate, you have a decent depth so you should not need to adjust the lighting this way....