HeyThere, how about approaching this differently? You shouldn't be scurrying around finding ways to disprove 607/1914 and the appointment of the Org; he should be scurrying around finding ways to prove it to you.
Yes, you do need to do your own research so he can't blindside you with impressive-sounding guff, and so that you can ask the right questions to show up the discrepancies in what he says, but get him to do all the work.
"So Jesus was installed as king in 1914 and ..." - "How do you know that?"
"When Jerusalem was destroyed in 607 BCE ... " - "All modern Bible scholars and historians say 587 or 586 so where do you get 607 from?"
"Then the 'slave' was appointed in 1919 and ... " - "How were they appointed? How did God make it known to them? What was the process?"
Etc.
Another thought (again inspired by poster Black Sheep): Don't jump around subjects. Stick to one question and, if he answers it to your satisfaction, move to the next one. If he tries to change the subject or says a lot of something that skirts around the issue rather than addressing it, bring him back to your unanswered question. It's been said that, if they keep wanting to move away from discussing your question, you're asking the right question so stick with it and tolerate no flim-flam.