Dual Flush Valve w/Handle, 2-inch

I have two issues with these units. The first is that all light flushes seem the same (about 3/4 gallon) and all heavy flushes (about 1.3 gallon) and that's good, but they each seem the same regardless of the position of the blue and red sliders. We bought 3 of these in total for all 3 toilets in the house and they all behave the same way. With a full tank, I turned off the incoming supply valve. Then after each light flush, I marked the inside of the tank with a pencil at the water level. I turned the supply valve back on and let it fill. I change the position of the blue slider and repeat. Pencil mark always at the same position. I duplicated that process for the heavy flush and same levels again but at a different pencil mark to the light flush. Unless I am doing something wrong the blue/red sliders do not seem to do much. The second issue is there is no disconnect of the flush lever. Meaning, the longer you hold the lever, the more water goes out regardless of the light/heavy flush selected. It is possible to empty the tank by holding the flush handle in the light flush position. Naturally that is not normally done, but how long before you let go of the lever is important. Try to explain to a 4-year old the difference between a 1-second hold and a 3-second hold. So are these worth it? Well, yes, kinda, but they need some tweaking. I now have it flushing smaller amounts by lowering the water level. It is still subject to the hold the lever down problem, but water volume is now good. In the picture, the "1" is where the top of the blue infill float valve was when only a single flush system. The "2" is where it now is as a dual flush. The "3" is the now, max water level. This is easy to do, but comes with a caveat that you may flood the bathroom if you do NOT put a clip (described below) back in correctly. DO NOT use the thing without that clip back in the correct position. Turn off the water supply valve as there is pressure under that fill tube and blue float valve assembly. You can remove the little clip in that assembly under the water level and turn that entire thing about 30-degrees anti-clockwise. Then push it down about 2" and turn it back clockwise. You may have to jiggle it up or down a tiny amount as there are slots it has to slide into allow it to turn and they are about 1/4" apart. Then put the little clip back in. It is a tricky job and it took me 5 minutes and 20+ tries to eventually get it in the first time. It's not hard to do, but just frustratingly fiddly getting hand and fingers in the right positions to slide it back in. BUT it is **mandatory** as you may flood the bathroom if you don't get it back in correctly. Without that clip the blue head is free to eventually rotate back to the sliding position. When that happens the water pressure will push the entire top part off the incoming tube. That's why it is designed to be rotated within the 1/4" slots. But the clip prevents it rotating around on it's own. MANDATORY!