My backup JB Vuillaume Strad copy was getting lonely not being played much so I decided to convert it to a “chin-cello” with these D’Addario Octave strings. Since I’m an adult advanced beginner I decided to let my trusty luthier exchange the strings and make the mods necessary to achieve the best sound from my 4/4 instrument. A bit of reinforcement on the same bridge; a bit of extra winding on the scroll-side of the super-thick G-string and slighly widening the nut for this low Hz string; removing the G-tuner on the tailpiece that lengthens the G; slight shaving of the tailpiece groove to insert the ball of the G, and voilà a viola-cello sound is yours! If you’ve ever approached a 3rd position A-string 2 octave scale with a bit of grimacing due to the high frequencies on your standard strings, then you will be as delighted as I was when all of your same G-D-A-E notes are down an octave. The sounds are pure (as long as your intonation is spot on) and to my ears, are more pleasing. Converting your backup to quadi viola-cello is an economical way to satisfy the urge to “go viola” as I viewed it. You could probably make the conversion yourself, but you would have to be skilled as a craftsman, and you still might not get the best results that an experienced luthier could achieve. He told me that he had done the same conversion on some e-instruments, but never on an acoustic violin. (The lower octave conversion on an acoustic instrument will not provide the same projection as it would on a viola or an e-instrument he opined, The latter coupled with an amplifier, of course. It’s all about acoustic wave physics and the size of the bouts of a viola and cello vs the violin.). He was also pleased with the outcome. You could probably make the conversion yourself, but you’d have to be skilled as a craftsman, and you still might not get the best result that an experience luthier because of chief. He told me that he had done the same conversion on electric instruments, but never on an acoustic violin. He was also pleased with the outcome. It’s always satisfying to know that you have expanded the Craftsman's skills. Give it a try. You will like it and the prices at KennedyViolins.