Unless you're getting an enema for medicinal purposes, capacity has no relationship to pleasure ... I can testify that my best enemas were less than (actually far less than) two quarts ... it's what goes with the enema that makes it a pleasurable and memorable experience.
I love when my hubby does all the nice things to me even before he inserts the well-lubed nozzle.
Our most recent outdoor enema session was an example of that ... he had prepared the enema, I positioned myself on my tummy on our picnic table ... he inserted the nozzle, gave me a few ounces of the clear liquid, then stopped the flow and began a full body massage, stopping occasionally to add a few ounces to my intesting ... the massage half took about 20 minutes or so ... starting with the shoulders, working down the spine, fingering every port of my posterior, then down my legs, right to my toes ... I think the gave me a few ounces at least five times.
Then he had my roll on my back ... doing the same thing ... occasionally added a few ounces to me ... his massaging of my frontal area was fantastic ... the completed the enema by openiing the flow as he played with my precious area .... it took about 40 minutes for the whole process.
I felt full, envigorated, emotionally high ... whatever you're supposed to feel I really felt.
I didn't rush to relieve myself ... but for a while I didn't think I could hold it much longer ... then I used our outdoor privy (It's in the garage). What a great feeling.
Then I returned the favor .... what an afternoon.
Like I said ... size doesn't mean anything when taking an enema ... my hubby proved that again.