Don't frag it when it's too small, it could overstress and possibly kill the colony.
Strong light, good parameters, and good, strong flow will keep the colony growing. Once it gets big enough, maybe 2" by 2" minimum you can start taking small cuttings. For GSP, a small bit of superglue on the mat bottom will help you attach it to a good rock.
Like most corals, it will grow slowly at first, and, as its surface area increases, grow rapidly.