Don't let them hide by not addressing the biblical evidence, which is powerful. You're absolutely right. They wave around a couple of convenient articles, but no one can argue them adequately, few see the glaring holes in their theories. They have no idea what those articles are trying to prove, which they can't. The problem with the JWs is that even though they claim to weigh all the evidence, they don't; all they care about is finding one source, one citation, one tiny argument however meager that supports their views, no matter how ridiculous. And that's why they don't want anyone pursuing higher education; it teaches you to think objectively. All JWs care about is having something in print. It comforts them.
I encourage everyone to read Jonsson's two papers recently finished completely discrediting the JWs on this.
Part I: http://kristenfrihet.se/vt pdf
Part II: http://kristenfrihet.se/vtsvar/vtsvar2.pdf
Also, read Doug Mason's work, don't have the link.
And if they argue the Bible on the 607 issue, you can bury them with this:
http://144000.110mb.com/607/index.html
And if that's not enough, here are 35 websites that deal with the alleged destruction of Jerusalem in 607.
http://www.144000.110mb.com/directory/607_bce_586_587_destruction_fall_desolation_jerusalem.html