I have a Perkeo II (with Color Skopar) which also uses 32mm push-on filters and several different brands appear to work OK. I admit to being spoiled by the more secure attachment of screw-on filters on my other cameras, but so far, so good.

The push-ons are pretty pricey in my experience, although a steal compared with some of the 37mm push-ons which apparently fit a couple of serious collectables.