First make sure it's the saddle that is source of objectionable noise. Go for a ride, and when you hear creak, ride out of saddle (OOS) momentarily without touching saddle, and observe if creak stops. If creak doesn't stop OOS, then something besides saddle is likely source of creak. Creaks in general indicate something is loose, broken or in need of cleaning and relube.

The source of creaks/squeaks are sometimes difficult to identify. I once swapped saddle, seatpost, BB, crankset and pedals looking for a noise, all to no avail. Eventually I got a flat rear tire and during repair discovered a loose cassette lockring (a new experience for me), which was the source of the elusive noise. I now always apply blue loctite whenever installing lockrings.

A quick google indicates SA saddles have some history of creaking, which mfg acknowledged and offered fix. Call SA for help, and let us know outcome. $175 saddles should not creak - my "cheap" B17 has never creaked.

These were std equipment on Schwinn "touring" models for years (1970s-1980s). I have an Avocet Touring that's still in good shape from my 1982 Schwinn. Be careful shopping for one as foam rubber padding tends to degrade to powder over time.