Actually you CAN get the H lift to stop when only part way up! Have done that many times!
On those lifts when you lift the handle to make it raise the plow or cultivators, the handle flies all the way up with considerable force right? It's the nature of the beast. When those lifts reach the end of the cylinder's stroke and the internal control valve "pops" into the bypass mode, the operating lever goes limp right? (If yours does not, the pump is worn, is leaking internally or the control valve or detent is stuck.) When in relief mode, you can move the handle up & down with ease just like if the engine was not running. The last little bit of the down stroke of the lever is what bumps a check valve out of the seat to let the implement fall. As long as you don't push that ball check out of its seat, the lift will hold any position. If you put your knee under the end of the lever & use your knee as a stop to push the lever back down far enough but not too far, you can stop the lifting operation and NOT unseat the check valve & it will hold that position! It has to have enough weight to create back pressure to hold the check valve in the seat hard enough to counter the handle's weight. The plow is easily heavy enough to do that.