Those are $90, screw that. Get the $25 tektros or the nashbar/performance rigs. As for clamping onto the 24mm section of a bar, you need 1mm brass or Al shim stock, available at any hardware store.
Those levers don't "push the cable," they push on the housing when used as interrupters. For normal use they work like any other lever. Some have a little rubber grommet in the hole where the cable goes, you want to pull that out if you're not using it as an interrupter.
Drainyoo, not everybody on here is a jerk, but very few of the regulars don't get at least a little annoyed when people ask questions like this that are easily resolved by searching.