Thanks, everyone, for the great tips. My 500 F4 is the AF-S model prior to VR-excellent glass that delivers when I concentrate on technique and give it adequate support. I do have a Wimberley WH-200 gimbal that is a joy to use. The suggestions of series 5 Gitzo without the center column seems the way to go. I don't mind the extra weight if it will deliver extra stability, and find some things (like a good support system) are worth the investment. I'm off to trek around in South Florida for a couple weeks in January and can't wait to put the new outfit (and myself) to the test.