Change moen turn shower valve to push/pull?

I installed a brand new moen posi temp valve for a customer.  She apparently was taken aback that you turn it for temperature and the water is full off or full on.  She would like it to be pull on push off and turn for temperature.

is there a replacement cartridge that can convert this valve to pull on push off?  It’s currently your run of the mill moen valve cartridge.  

She’s a strange lady and has no regulator coming from the street, but is terribly concerned that she can’t regulate her shower head.  (She has iron pipes and her pressure sucks and the shower would make me angry because it doesn’t have enough pressure but she thinks opposite)

I doubt it, but you should be able to get a showerhead that regulates it back a bit I think.

We have an "eco or low flow" type showerhead and it emits way less pressure and volume than just the tub.

Is it in a shower or combo tub/shower?

If it’s a standard alone shower I would look to see if you could add the internal diverter to the valve.

While not ideal, it may allow flow to be controlled by reducing the shower head flow when moved towards the tub position. 

On edit: I was thinking Symmons, not Moen. It looks like the valve body is different on the posi temp with diverter vs the shower only, and not just a case of having the diverter feature in the casting with the valve blocked off. 

It’s a walk in tub with tub spout and handheld shower.  My other option is try and find a flow restrictor to put inline to the handheld shower.  20ish years old, company that did it long gone, valve was proprietary and bad so we went with a normal one.  She approved it, i’m not on the hook for anything, just want to help her out.

She is amenable to either.  

There are little ball valves that you can get that go inline with the shower head like these. Is one of them enough?

I think, at least around here, the push off valves are not legal to sell anymore because there is no pressure balance system to prevent scalding.

I could be totally wrong...but I don't think so. 

I'm confident about one thing, though.  You will have to change the assembly to change the type of operation.

Patrick said:

It’s a walk in tub with tub spout and handheld shower.  My other option is try and find a flow restrictor to put inline to the handheld shower.  20ish years old, company that did it long gone, valve was proprietary and bad so we went with a normal one.  She approved it, i’m not on the hook for anything, just want to help her out.

She is amenable to either.  

Adding an inline vacuum breaker to the handshower hose connection may be enough restriction to limit flow without any other changes   

Moen posis are a pain in the ass. I've never seen one with an adjustable flow, personally. You might be stuck with an inline diverter, like someone else said.