I can't find any rhyme or reason to it, but FGs that use TU such as Elidnis and Gemini will TU spam RoLs before anything else. However, there does seem to be a point where they'll TU bigger things as well. To wit, Gemini TUs four RoLs, then decides to switch to Dragons. Hope was at 12, so it couldn't do any damage to me one way or another. Regardless, RoLs seem to be at the very top of target priority no matter what is on the field.