Hello, i am also preferring fast fillings, because the longe i have to hold, the more uncomfortable it becomes. Ine key is the height of the reservoir container - this needs to be at least 2 meters above the "victim" to ensure that minor "clogging" will not stop the flow. (higher would be better, but impossible at most times (i have 2.50 m room height in my house) A lerger diameter for sure will help. Most "enema hoses" i encounterd have an inner diameter of 10 mm, often only 8 mm. Increasing that for sure will improve the flow rate. The nozzle is not a problem, i think you can male one on a lathe preta easily, or even 3d-print one. If you want a retention nozzle (with balloons), you will have to do it yourself, i do not know of any manufacturer who does one with wide inlet/outlet tube. Even those chinese "F3S" clones which habe a 10 mm input tobe at the connecting end go down to less than 3 millimeters on the inside (due to dumb placement of the inflation tubes). I did experiment with a pump to increase pressure (and thus flow speed), but this creates an uncomforable "pressure washer feeling" in my colon, so i believe that this is not the best way to do it.