I can assure you that Ham doesn't understand evolutionary biology, nor does he understand how science works. Ham and his ilk are not willing to follow the evidence where it leads, and to change his position as a result. He knows the conclusion he wants to come to, and works backwards from there.
I think you are right, but bobbied is right too. Ham knows his own arguments and how to present them in a way that may sound good and deceive the uninformed. He has lots of experience and practice doing it. Complicated truths are often hard to defend in a short space of time allowed for in a debate, but simplistic attacks that may require involved responses are easy to make. Ken Ham's bat-sh-t crazy ideas won't necessarily preclude him from coming off better looking in the debate.