My frame now has a top tube of 52.5 cm. Now, a 50cm in the bike i rode (traditional frame) had a top tube of 51cm and the 52cm bike i rode (traditional frame) has a top tube lenght of 53cm. so there is a .5 cm diff either way. I am guessing with additional adjustments to the saddle and bar position, that the 52 may just work. or is .5 cm on the bigger side just to much to give ?