I'm looking at building this bike up for my brother as a bit of a do it all bike for riding round London and also some off road stuff, I guess a kind of gravel inspired build! I'm just not sure on the sizing of this frame I have! It measures 19" from the middle of the bottom bracket to the top of the seat tube. Would this be considered a large, suitable for someone 6'1? I would like to add drop bars and a shortish stem. I also have a steel version of the frame the same size that I use to walk the dog and I can ride it but do feel a little cramped on it but it has slightly swept back bars and I'm 6'3.