It's not difficult at all. Several companies now make vibratos for flat tops so you don't have to spend a tong. GFS makes a vibrato with matching bridge that loads from the top of the vibrato. This is a result build of mine with the GFS matching set. The vibrato is a roller. and the bridge can be adjusted forward and backwards as well as at an angle in addition to the saddle adjustments. The whole thing was about $70.