Prologo scratch pro 143 on my fast bike and Selle Anatomica on my all around/tourer. Took 5 tries for my fast bike. Used the Scratch pro for a 4 day ride down the Oregon coast this past summer, 80-100m per day, no chafing or other problems. I do concur on getting your butt conditioned. For me it took close to 4000m in the past two years to feel like I had adequate toosh conditioning.