About the loop depth - this is the total width of the loop in inches. The example I loaded was the 3 foot ribbon cable loop, and with 9 turns on 0.050 centers it would be 0.45 inches deep (0.050 * 8) = 0.400
The wire length would be for single conductor wire, not ribbon cable. Divide the length by the number of turns for the amount of ribbon cable you would need.
Parasitics in the loop - inter turn capacitance in particular - are not taken into account. They will limit the high frequency response of your loop, so the estimate of maximum frequency is probably off.