No, I don't. I don't have 2TC as my impression is the resulting IQ is not good enough most of the time. So, like I said, I was surprised by what I saw. Those guys I mentioned use D300. D3, D700 should do better.
IMO, 1.7TC is fine with 300f2.8. Used that combo before on D300...back then :
http://www.birdphotographers.net/for...ad.php?t=28300
http://www.birdphotographers.net/for...ad.php?t=27390
Found one large large crop BIF shot (same hawk as in other shots) with D300. Here it was swooping down to catch that american wigeon (or whatever was left) in one of the above photos.