In the U.S. many of us are familiar with, and admirers of, Alfredo Rolando Ortiz, who recorded many albums of Latin American harp music. Of several books he has written, “Latin American Harp Music and Techniques for Pedal and Non-Pedal Harpists, copyright 1979, has the first 32 pages devoted to technique. The remaining 50 pages contain music. Page 22 has helpful information for filing the fingernail , and an illustration, so that one could either use the pad of the finger for pedal and non-pedal harp, or the nail for Paraguayan harp or possibly guitar. Perhaps these pages will enable you to be successful enjoying both guitar and harp. His web site offers both his recordings and his books. Enjoy!