I used my D2X and 70-200 VR f2.8 on a Manfrotto 055 pro tripod and found it very wibbly-wobbly. Consequently most of my shots were blurred!
Also at almost 2kg I would not describe the 1000mm lens as 'not heavy'
I suggest a much sturdier tripod and heavy duty head especially with the slow shutter speeds f11 would yield.
Lens spec
here