Custom dimensions — +12 in block

Surcharge line added by the 3D tower configurator for custom dimensions: one line per started 12 in block. Taller legs — each extra 12 in of leg height above the family standard. Wider spacing — each extra 12 in of body length versus the 4 in tap spacing layout ((taps − 1) × (spacing − 4 in)). Not sold on its own: the tower line it belongs to is named in the line properties.