With the Tall Corner Custom 90, configurations add up vertically (not illustrated, see Tall Custom Vertical).
Variables to set in the Dimension tab:
Depth2 (D2)
Width2 (W2)
Variables to set in the Shelf tab :( these can be set independently for each configuration)
Shelf Corner Depth 1 [config] (SDC1 [CFGS])
Shelf Corner Depth
2 [config] (SDC2 [CFGS])