I have a couple of broken Pop-a-way rainbirds that need replacing. I've been at this residence only a couple of years, so don't know the sprinker system histery. I've gathered (but not sure) that pop-a-way rotors are no longer available... Is the Maxi-Paw an acceptable substitute? I'm assume I'll find common PSI / range specs between the two. What about replcement covers? Thanks for the help!! Mike