Light trace is the best time to do swirls. You can pour into molds at this time also unless you want to do a fancy top. I do individual molds and light trace is the easiest to pour because you have time to pour each individual mold.
If you don't want to gel you need to keep it cool. You can put in frige or freezer, put outside if it's cold enough, put a fan on it, I can just set mine on my stone counter tops as it pulls the heat out of it. So anything to keep it cool.