I had the same situation...my bike came with the stock 20mm setback carbon seatpost which required me to move the saddle all the way forward to get comfortable. It always seemed that I sacrificed a lot of saddle rail suspension and road buzz reduction by moving the saddle that much. I chanced upon a zero setback aluminum post and was able to keep the clamp in the middle of the rails. By positioning the saddle there, I found the sweet spot for comfort, power and road buzz reduction. I tend to make whatever change I need based on my body and pretty much disregard calculators and formulas, even if I have to spend a couple of dollars to get there.For me, riding keeps me well, it's worth the money.