You can get the frag now but the growth that is measured will only be from the date we start. That's when a special code word will be given and a photo must be taken with the coral and code word together. You can get a frag now and let it settle in your tank but it must not be larger than the minimum size limit we set per each type of coral. If I were entering the contest I would get my frags now and let them settle so when the contest starts they will be ready to grow and already growing. The key is timing. Remember were not going to be putting all of the coral entries side by side to determine which is taller, etc. Judging will be based on growth rate, health of coral, patterns of growth, etc.
You can frag the coral now as long as by the time the contest begins it has not exceeded the size or polyp count mentioned in the rules.
As far as choosing a coral, pick the one that will grow fastest in your system. Only size and health of the coral are judged, not color or how rare it is.