One thing you can measure objectively in regards to picking an appropriate saddle is to measure your sit bones. You can google DIY methods, or go to a bike-shop which has one of those machines which measure them for you. A smaller width between your sit bones would possibly dictate the need for a narrower saddle (132mm, for example).

Other than that, trying out used saddles from a place like eBay is a more affordable option until you find one you like.