Wow! SB910 and SB700 produce SB900s and SB800s? I must be missing something! My initial breeding pair of SB800s produced only more SB800s, twelve in total, probably because the SB900/SB910 models had not yet appeared on the scene. I will have to try again!
While I haven't tried photographing hummers yet, we do maintain a feeder and the little birds will feed with us standing fairly close to the feeder, within eight to ten feet or so. A simple test with your 70-200 mm lens at 200 mm will tell you how close you must be to fill the frame with a bird. If 200 mm is not enough, you may want to try a Teleconverter (1.4, 1.7, 2.0) before investing in a longer lens.
I have successfully triggered remote SB800s at sixty feet or so at night during many of my law enforcement photo sessions. As long as you maintain good line of sight between remotes and the on-camera master/commander, it may work for you in your shaded area.
I would try CLS before investing in Pocket Wizards. You can fashion snoots for your SB800/900 remotes from aluminum foil, black background paper, etc. and attach them with rubber bands. Experiment with these at different lengths, once you find out how close you can place the remote speedlights to the feeder. Shorter snoot equals broader beam, while longer snoot equals tighter beam. I use Cinefoil for speedlight snoots, which is a heavy aluminum foil that is matte black on both sides. It comes in rolls 24 inches wide by 25 feet long, and costs about $30 US. Experiment also with the zoom setting on the remote units.
With a little testing, you can likely work out the configuration details and then wait for the hummers. I don't know what your background is behind the feeder, but you may want to consider placing a piece of black foam core behind it to isolate the birds from it. If it is far enough behind the focal plane, it will go to total black.
Thanks for dropping in. I look forward to seeing some of your images.
You may want post this question in the Nikonian Wildlife forum, as there are several excellent hummer photographers there.
Hope this helps a bit.
HBB in Phoenix, Arizona Nikonian Team Member
Photography is a journey with no conceivable destination.