Don't feel too bad - I have had my saddle for over 5 years, ridden in almost every day and tons and tons of trail miles. And occasionally it still squeaks. I've done the baby powder thing, but near as I can figure it's in a spot the baby powder can't reach.
Make sure that you move that saddle to all different angles to allow the baby powder to get where it needs to go. For example, tip it up onto the horn to allow the powder to shift forward and get in where the stirrup bars are corrected.
We use baby powder on all our saddles. I haven't used oil in a long time. We clean then use a leather conditioner then baby powder after they are dry.
My husband got a new impact gel saddle pad for his birthday and the saddle fenders on the wear leathers was making all sorts of noise, so we powdered down the saddle pad too. Worked at getting rid of the squeak