Just to perhaps a help to others, Foreverdl, I believe, is referring to what is technically called a ball valve (you turn a lever about a quarter turn for max flow)and it would be perfect. If I'm wrong Foreverdl let me know and we can figure it out. Foreverdl you have hit the nail on the head with a better valve. All the shut offs that came with the bags leave a lot to be desired. The only one of the simple click on/off clips that really was easy to use and dependable was the old metal one. But they don't adjust the flow. And the others with sliders etc. don't hold up or work well. They are really designed to be cheap disposables and work poorly. I think a trip to the home center is on my list of things to do. Thanks for the tip.
And just because we are talking about equipment, this advice. Never fool with the combination water bottle/enema design. They are a pain to fill and I always wonder if they dry out. The open top bag is much easier to use.