But do note that Ham is a good speaker (and with a nice sounding accent). The people at his position are generally not going to be walk-overs in a debate, because such debates are pretty much all they do.
Some of the things I would suggest are sort of like flanking maneuvers. With such a vast array of scales in the universe, from galaxy clusters to bacterial flagella, does it make sense that only one god was at work? Wouldn't it make more sense if the different aspects were handled by specialist gods? Would a god who could create the big bang really be shoving his hand up a sheep's butt to tweak a gut bacteria? In science different forces and effects work at different scales. Drug resistance, river erosion, and star formation aren't the same specialties, and if they all manifest a higher power then they probably don't all manifest the <i>same</i> higher power.
The thing about creationists is that they find the idea of polytheism anathema, probably worse than atheism because it's a competitor, not an alternative. It's been ages since they've never had to argue against it, and they've hardly ever had to do so logically, other than "my God can beat up your gods!" And none of the weak arguments they advance for creationism would indicate that one god makes more sense than hundreds of thousands of more specialized gods. When they introduce a place for supernatural forces, they're opening a can of worms that is not at all limited to the Biblical accounts, and I don't think they realize that.