Only most crazy guitarists would want to play 3 necks at the same time, and the article mentioned that Steve Vai as one, which I fully agree. You also need to have a good build and a very strong back to carry the weight.
Scott Yang's Playground
Faith, Technology and Randomness in Life, According to Scott
Oct 31 2004
Well, did you see the photo linked from the comment? Five necks! How on earth can you reach the bottom neck?
Richie Sambora had a triple neck acoustic, one 12-strings, one 6-strings and a mandolin. I thought that makes sense.
Use your toes, of course…