I have almost the same kit as you. I don't have a sb-900 as I have been waiting for the sb-650 so it doesn't bend the hotshoe. I don't have a 14-24 as I have been waiting for the 35 1.4.
the 105 with VR is really nice with a tc-20eIII. it fits on my d700 much nicer with the tele on than off. really snug in my hand. doesn’t seem to affect the IQ at all (unlike on the 70-200 vr2) and who really needs to shoot at that extra stop with a micro anyway. if the subject is in a tight space I can take the tele off and just use the 105, and if i am really desperate I can shoot it at 2.8 with the tele off.
my tc-20eiii stays on my 105 micro all the time and just comes off for the occasions i need it on the 70-200 (like the soccer match i’m shooting on Sunday).
I use a gt3541LS, a markins m10, a d700 with grip, a RRS L bracket for gripped d700 and a RRS macro focussing rail. That all cost a fortune. Be prepared to spend more on this stuff if you get into macro! If you dont have a GOOD tripod, forget about macro work. the 105 with the TC-20eiii goes up to f/90!
210mm f/16 1/200 sec ISO1400 handheld. unprocessed raw fileconverted to jpeg in lightroom 3.
210mm f/6.0 1/400 sec ISO1600 handheld. unprocessed raw fileconverted to jpeg in lightroom 3. This butterfly was moving fast! AF-C bang on, even with tele on.
These are just examples, not my best shots using this lens.