Some people swear by leather Brooks saddles, which work by the same principle except that the leather stretches more than plastic and so the rail mounting needs to be re-tightened occasionally. The leather needs to be rubbed frequently with oil at first so it is soft enough to change its shape to adjust to the shape of your pelvis, and must be protected from rain. Once you get past the initial months it's said to be the perfect saddle, but I prefer not to go through all the trouble. One of the best saddles I have used is the regular racing Flite, which has next to no padding but a flexible shell and soft Titanium rails. I normally avoid the Titanium hype but this is a really useful application.
Titanium is much softer than steel.
Unfortunately you can't adjust the tension, so after a couple of years it sags and becomes unusable. The saddle height is very important. If it's too low, you have much less strength when pedaling, and if it's too high you'll rub your thighs sore. Adjust the height until you can pedal backwards with the heels of your shoes on the pedals, with fully stretched knee but still touching the pedal when the pedal is in the bottom position, without rocking your hips. I prefer the standard angle where a bar laid on the nose and back of the saddle, parallel to the top tube, is horizontal, but some people prefer the nose slightly up or down.