A network for historic guitars and vihuelas
Hello Rui. 60cm is a bit on the short side, even for the 19th century guitar, but not unacceptably so. You will see anywhere from 598/600mm to 655mm but I suppose an average would be in the 620 - 630mm range.
I like the 62cm string length for my personal instruments. Players of modern instruments sometimes feel a little cramped until they get used to it. When they find how easy those monster stretches of Legnani and a few others are they are sold.
I make a Viennese/Stauffer model that has a 598mm string length. It's a wonderful little guitar for studio/intimate playing but find by stretching the length to 610 or more there is ample punch for the concert stage.
The terz range is generally +/- 56cm so 60cm is pushing it a bit but doable with the proper strings. I find that 56cm is perfect for the terz instrument so that's what I make mine at.
Keep us posted Rui, I've not seen many instruments from 19th century Portugal and none from Madeira so I, for one, would be excited to follow along.