Go ahead & give them a try. They worked really well for my cats - I used soft paws while training my cats to use their scratching posts & mats, & to leave the couch alone. If you're nervous about applying them yourself, ask a vet or groomer to apply them for you & show you how it's done (they'll charge for it, though). The www.softpaws.com
web site has good instructions too, answers on their FAQ page, and you can even contact them with specific questions.
Another thought - try & look at your house from your kitten's eyes, and figure out why he seems to prefer the couch to his scratching posts. Is the couch sturdier than his post or scratchers? What kind of fabric is the couch made of? Does he scratch the corners of the couch vertically, or the back or the couch horizontally? Find (or build) a scratching post or scratching surface for him that has the properties he seems to prefer, and then make the couch unappealing, by attaching double-sided sticky tape or aluminum foil to the areas he scratches on. Also, make sure his allowed scratching surfaces are near places where he'll naturally want to scratch - the places where he spends most of his time, and especially near where he likes to nap.
Sorry for the mini-novel!
Hope this helps