Chatting with a local mechanic, a shop will often chop the seatpost before sale, so you shouldn't have to worry about this excessive but when you do must, Really don't worry since it can be done! Just for reference this was for your size 51cm and my saddle top is https://damienrktjt.blogtov.com/7078639/the-greatest-guide-to-bicycle-store-near-me