Hello everyone!
I'm looking for an all-road bike to mount with a GRX Di2 2x12 drivetrain, and after careful consideration, I think this frame is the best choice.
It's my first build, so please bear with me; I'll be asking one million of questions

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First, the size. I'm 180 cm tall and ride with a 74 cm seat height (A). I currently have a Propain Terrel CF, where I set the saddle's anatomical center from the bottom bracket to 17.5 cm (C), and the distance from the anatomical center of the saddle to the shifters is 78 cm (B).
Do you think the CFR-505 SL in size L would be right for me?
Seatpost with a 2.5 cm seatback or 0 cm?