Share 'Early six course Spanish guitar: fretting and stringing'

I would be grateful for any information on two aspects of the Spanish six (double) course  guitar introduced there in the second half of the eighteenth century and which continued to be played into the nineteenth: Fretting: - as far as I'm aware all extant instruments of this type have fixed metal frets on the neck but, of course, some could be replacements for earlier tied frets especially for…