Have you considered a Bontrager Affinity? I've only done a single 30-mile ride on my Affinity RL WSD but it's a 154 and feels more t-shaped to my inner thighs than a 143 Specialized Ruby or a Fizik Donna, even though I feel like there's a wide platform to support my sit bones. There's a 30-day return option, at least where I bought it, so I'm giving it a try even though I haven't ruled out the recently purchased Ruby.