I think you need to try several. I have found that you can get nice new (or nearly-new) saddles at bike swaps.

Buy a few different shapes and sizes and experiment. Sadly, I don't think that you can short-cut this process.

Sell the saddles that don't work for you at the next bike swap...or donate them to your local bike kitchen...or sell them on Craigslist.

Brooks are expensive so that is not a great place to start. Brooks are not "magic" and they don't work for everyone.

Good luck!!