If you can see the slave cylinder move a lot (the rod at the transmission) it's something else that is the issue and the movement to push the TOB out has increased to the point where you have little room until the pressure plate springs back and grabs the clutch disc, which is why its engaging almost when you let off the floor. Hydro clutch setups are the best, but only when brand new correct parts are used IMO, no machined or cut flywheels or spacers. If there is a popping noise, peek inside and see if you can see something moving around in a way its not meant to. I'd suspect the TOB and clutch fork are making noise due to something not fitting right, IE wrong clutch setup or flywheel. There is not enough movement and that can only be caused by the spacing being wrong on the flywheel and pressure plate. Whats your setup again?