Stargazer, I went through the same thing with my first colt coral. The things get huge. Cut mine into thirds and now they are all huge again
I sliced mine diagonally, using a brand new razorblade. Got about 3 tendrils when the cut was made. Mine never slimed. Try not to get too much of the body/base of the coral. Just enough to give you some surface area to attach the bottom to something.
The two frags I made from the original were attached to two dead coral skeletons. One was a plate coral skeleton and the other was a dead lobo skeleton. I didn't use glue. I used regular rubber bands to hold the coral against the old skeletons. Eventually they colt frags grew around the rubberband, just like a chain around a tree. No problems at all. They are all three huge now.
Hope that helps. I have a post out here somewhere showing the before and after pics. Give it a search if you want.