Great! Glad to hear your rock arrived in good shape without any funky smell. That is always a good sign.
As for the wife...Well, forgiveness is usually easier to get than permission.
Luckily my better half is pretty supportive when it comes to buying stuff for the tank, just not when it comes time to do the maintenance.
You will probably need to bust out a hammer and chisel to get the most accurate break on the rock so that you end up with a couple of big rocks instead of a bunch of small rocks. Don't forget the saftey glasses.
Coraline is photosynthetic and will need light to grow, but is very hardy and can sustain lower levels of light until your tank has cycled and has corals.
Try to position the rock so that you have as little as possible touching the sand. The more sand that is exposed the better. It will help with water flow and reducing the amount of deterious that gets trapped. One suggestion is to get some 2"-3" pvc and cut it to the same length as your sand bed is deep, and use these to set your rocks on. Cut them slightly short so they do not stick out of the sand bed. This will keep your rocks from settling and sinking into the sand. Most stuff on the rocks will die, like coraline, sponges, etc, if buried in the sand.