Long term advice when debating theists.

[Hatshepsut]

...to debunk science with science...

I'm a bit unclear about what this term means. Is debunking the claims of others what science is supposed to do? Most scientists don't waste their time on the science/religion debates. These shouting matches will go on to kingdom come (pardon my choice of expression), and quite frankly science doesn't really have an opinion on many religious matters, including existence of deity.

For instance, that our planet's date of formation is >> 6 Kya is well known, and need be debated only in court in the event creationism is proposed for curriculum in public schools. I think this issue gets rowed over by the person on the street only because, while access to churches which teach creationism is easy, access to the methodology which establishes geologic time scales is harder to come by. Basic principles in the hard sciences require a lot of study and mathematical maturity to grasp. Evaluation of secondary sources for reliability is also subtler than it looks: Precisely why is Nature a better journal than Answers? The average person simply doesn't know until attending college and often not even then.

Therefore, the debating arena is condemned to remain as sterile as the surface of Venus. In other words,

... you are very likely not debating the same thing.