LTA's don't reproduce asexually, they only reproduce sexually. If your LTA is 5 to 6 inches round, they get a lot bigger than that. Their disc gets about 18 or 20 inches accross maximum. My purple LTAs disc is 10" and it has a lot more growing to go. Please ...I beg you..do not attempt to cut your LTA in half..it will definitely die. The only anemones.. that I know of.. that reproduce asexually is btas, magnificas, and some haddoni(but this rarely happens with the haddoni).
Here is a pic of my purple LTA with its pink skunk.