70-200mm VR & 1.7 Tele?

I own a 80-200mm nikkor, great, fast and very crispy lens. I also have the 300mm f/4 but find it very slow to focus compared to the 80-200. I also use a 1.4 teleconverter on the 300mm, it stays very sharp but the focus speed comes in at a snails pace! pretty much useless for birding. So...my thought is this,

Buy the 70-200mm VR and the 1.7 teleconverter, this will get me out there, but how fast will it focus? I wondered if anyone had input, or used this same combo..
Thanks,
Rob
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D70s
D1H

Nikkor 80-200mm f/2.8, Nikkor 300mm f/4, Nikkor 50mm f/1.8, Tokina 28-70 f/2.6-2.8, Sigma 105mm macro