It is many years since I used a 12 string capo - a Shubb - which I lost long ago! Had 6 string Shubbs as far back as I can remember.
Right now I have G7 ( easy to put on and off, but not so good higher up the stick), Planet Waves (good and functional, but the rubber wears out quickly), Shubb (best all-round - I have used them for 30+ years).
None of the above are that suitable for use above the 5th fret. IMHO, the Shubb is best.
BUT! A couple of years back I bought one of these and I just tried it up as high as the 9th and it works great! Don't know how well it will last, but I just might start gigging with it - it seems great and it is obviously easy to change keys quickly with it! Might be a bit pricey at £24, though!http://www.imuso.co.uk/Accessories/Guitar-Capos/19731-/Glider-Capo-Greg-Bennett-Design-Rolling-Capo
Hope this helps.