What makes a good gut string?

What does really make a difference for the quality of a gut string: in my opinion, the first factor which really affects the final quality of a string is that the numbers of gut strands used is balanced to the gauge we want to obtain. This is why they used bigger guts for bigger strings, and smaller gut for smaller strings.

Try to imagine an extreme situation: If there will be not enough strands (like two) the string will be hardly polished and weakened.

This is why Paganini asked for cantini made out of four strands, when normally they were of 3...

twisting is the main factor to the capacity of our string to vibrate....

Imagine a string made with too many strands, like 100 (for a normal small gauge): it would be almost impossible to twist it and it will become stiff. Imagine a big rope of a ship. There is a close relationship between the number of strands and the twisting to obtain stiffness, resistance, or elasticity....