Most of today's cylinders allow you to strap a reed switch on them
that way you could get two positions on one cylinder by reading the state of those and stopping the air supply at a particular point until a weight is reached and then progress to the next point until you have the desired weight and at that point it would shut off completely.
Seen this done in automotive welding fixtures where something goes from fully open to load parts then to a pre clamp position until everything is in place and then to clamp position and its possible to add more than 2 to get a more precise position.
Reading reed switches is very easy and relatively cheap too.
There are also inductance types that allow you to control stroke points almost like a potentiometer reading but I don't have any experience with those.
I have seen cylinder marked with a scale so operators can slide the reed switch and know where to position it to change the stroke for a different component and I think that with a little thought that process could be converted to flow or an approx weight. eg. 2mm movement may equate to .5 liters flow rate or an extra kilo etc. Don't ask me to do the real math though.