I have a Gitzo 1415 (I think that's the legset #) which weighs in at about 10 lbs (it's an aluminum legset, not the carbon fiber, and without a center column), coupled with a 1525 pan-tilt head. That would be more than sufficient to keep your 8x10 stable - I've shot my 14x17 with that combo. I suspect a definite part of your stability issue is the Kodak 2D - NOT the most rigid camera in the world.
A big part of the stability equation is the center column or lack thereof. By not having a center column, your tripod becomes far more rigid and stable at the camera level than it does with the center column extended. About the only exception to this rule would be something like a Majestic or one of the aluminum Manfrotto tripods with the cross-braced geared center column.
That said, don't fool yourself into thinking that you must have a tripod that weighs as much as your car's engine block in order for the camera to be stable. I also have an Induro carbon-fiber tripod (CT-314. It's a four-section legset that will fit in a full-size suitcase with the head removed, which I bought for travel purposes) that weighs in at 5 lbs-ish (6? I forget, whatever it is, it's very light) that I would trust without question for anything short of an 8x10. I routinely shoot my 5x7, 5x12 and whole plate (6.5x8.5) cameras on it. I shoot night photos all the time with that tripod - check out my recent night images in the gallery here from San Francisco (5x7) and Washington DC (5x12) to see how well it does. My camera is a Canham, so it's pretty light itself, and especially in the 5x12 guise, susceptible to cross-winds.