I noticed the size of Harmony device is quite different between what the sliders on the left say and the actual size on the dicoms as shown in the attached picture. Measurements of the cardiac structures on dicoms are accurate, so I am confused about the cause of this.
Everything looks good. You specified a radius with the slider and then measured the diameter, which is expected to be 2x larger. In most other devices we use diameter to avoid this confusion but for some reason we kept using radius values for the Harmony device.