Convert from palmo [Spanish] to fuss [German]

Unit Definition (palmo [Spanish])
The palmo is a traditional unit of distance in Spain and Portugal. The traditional Spanish palmo equals 9 pulgadas or 1/4 vara: this is about 20.9 centimeters in Spain and a little more than that in Spanish Latin America. Under the metric system in Spain, the palmo is an informal unit equal to 20 centimeters. These units are based on the width of a person's outstretched hand, from the tip of the thumb to the tip of the little finger, a definition identical to that of the English span.

Unit Definition (fuss [German])
The length of the fuß (or fuss) is the German foot. It varied somewhat; the Viennese version was equal to 12.444 inches or 31.608 centimeters, while the Rheinfuss (Rhine foot), used in much of western and northern Germany, was equal to 12.357 inches or 31.387 centimeters. In Bavaria a shorter fuß of about 29 centimeters was used. There's no change in the plural.