Yes, fitting them is easier done than said! You'll only need to read the page of instructions once.
All classical guitar strings are compatible with String-Plates.
Yes, String-Plates do not require any modifications to the instrument and you can go back to the traditional method of tying at any time.
The procedure for fitting the String-Plates is the same as that for changing strings: replace one string at a time and tune it before replacing the next. That way the instrument is stressed as little as possible.
The instructions show the best way of tying the string.
With the traditional method of tying, a string can easily come untied by itself, lashing violently against the soundboard and causing serious damage.
String-Plates solve this problem.
Yes, using the main hole. No modifications to the instrument are required and you can go back to the usual method of tying at any time.
It's the angle formed by the string between the point at which it emerges from the cordal block and the point at which it rests on the saddle. The String-Plates leave this angle intact, as may be seen from the photos.
The double hole solves only the problem of the angle; it doesn't solve the lashing of the soundboard (it sometimes even makes it worse) and aesthetically it's similar to the traditional method of tying.
The triple hole solves the problem of the angle and the aesthetic problem, and it almost solves the problem of the lash.
On the other hand:
• it should be introduced when the instrument is being built
• it can also be introduced on an instrument originally created with a single or double hole, but only by a skilled guitar maker
• it is irreversible (and is not recommended for historical instruments)
• fitting the strings is not easy.
Of course, like everything in nature.
They are made of an aluminium alloy that is very durable and light. The most wear is caused by the sixth string, and by the basses in general. But there are guitarists who have been using the same String-Plates continuously for fifteen years. A set consists of 6+2 String-Plates. I think we can safely say that durability is not a problem!
The weight of six String-Plates is 0.72 g, from which you have to subtract 0.37 g of strings (tying with String-Plates requires less string than traditional tying). The total weight added is therefore 0.35 g, equal to a square of standard 80 g paper with sides of 6.5 cm.
Guitar maker Luca Waldner first conceived the idea of String-Plates in 1995, but it was only in 1997 that they assumed their current form. Since then, they have been used in all his instruments. They were developed as a solution to the problems created by the traditional way of tying strings.