Hi Ian, how is that 200-400VRII & 1.7TC combination working for you?
I used to own the MKI version of that lens and really didn't like with TC's, curious if the MKII is different in that regard.
I find you have to pay close attention to AF correction with regard to using the mark II with the tc, I find that the 200-400 has a shift around the 20m distance where I need to use a different focus correction than I would need to use closer than 20m, using the 1.7 tc only magnifies this problem.
Once I correct for this I find the 200-400 handles the TC rather well
Bellow the 200-400 II with the 1.7 wide open F6.7

I just picked up the 1.4 III and I find it better than the 1.7 and AF is hardly hampered see my next post