I was OK with riding on plastic bags over the saddle, when it was raining .. Ireland in March and April.

I melted a table spoon worth of proofide in an upside down hot saddle decades ago & its been fine ..

just use the Pleather ones in this locality . Fizik Vitesse is kind of B17 like

took the Brooks off so they dont get moldy (on their surface in the basement bike storage .. moved them upstairs )