No small-light tripod will work. Ignore anyone who says otherwise. The physics of the system will dictate why a light tripod wont work, even if it is an expensive tripod. And a cheap tripod is just a recipe for disaster. You have a few hundred grams of shutter-mirror mechanism (less weight in DX cameras) slapping at great speed, the rotational torque and momentum are quite profound. You need a structure with enough inherent rigidity to avoid oscillation down the tripod legs. A cheap light tripod will only amplify the motion.
A general rule of thumb is the tripod+ head should weigh at least 1.5X the weight of the camera + lens it is supporting. This quickly pushes you to a 3.5kg or more for a 200mm 2.8 lens. Carbon fiber and modern construction can reduce this, but there is a limit.
The Pro solution is an expensive carbon fiber tripod (usually by Gitzo), and a decent ball head (really right stuff BH-40 for light-weight).
Bean bag would work better than a cheap tripod, but I have never tried. The reason here is that the bean bag instead of trying to produce a solid rigid support like a tripod gives a dampened support which absorbs camera movement. This will only work for smaller lenses.
Hand holding can be much better than a cheap tripod with good technique. Use a 2 second timer so your finger press is stabilised and the mirror slap is not present. Standing in a stable position, preferably leaning on something for support. The usually high iso + appropriate aperture to get a reasonable shutter time is require, VR/IS will help a little.
I know someone who was trained in the army as a sniper, he hand holds giant telephoto lenses to great affect.
The other thing is mirror slap is worse at the shutter speeds of 1s-1/20s . Avoiding these shutter speeds helps a lot.
And Nikon is horrible for not putting Mirror lock-up in the low models.!
