Seriously, don't declaw your cats. If you keep your cats indoors, it can be a pain in the ass...but you got the cat(s). Time to deal with it. Their claws are their only defense. If they get out, you'll probably want them back someday...
I have two cats - both of whom were quite happy tearing the shit out of my furniture. I've found the "No Scratch Spray" stuff to be completely worthless..but here's what works.
Get a wide roll of double-sided tape, and coat the arms and backs of all of your furniture with it for a couple of weeks. Sure, it looks like shit..and you won't be keen on putting your body against it. But your cats will dislike it even more than you do.
They'll jump up on the furniture to start clawing up your stuff, and stumble off immediately. They can't stand the stickiness.
Don't bother trying the aluminum foil trick, as it's done nothing for me.
Also, keeping your cats' claws trimmed helps TREMENDOUSLY. You'll hear veterinarians tell you not to trim your own cat's claws: that's crap. If you look at their nails, the tops of the nails are an off-white color, and it starts to get pink closer to the paw. If you get a standard set of nail clippers, you can cut their claws just above the pink area without worrying about doing any damage. JUST BE SURE NOT TO CUT INTO THE PINK AREA NEAR THE BOTTOM. This will not only REALLY piss the cat off, but will cause him/her to bleed...you'll actually hurt 'em.
A huge part of the reason cats scratch stuff is to keep those claws trimmed down.
Lastly, I have a spray bottle in every room where there's furniture. I keep it full of water, and readily accessible. When I see a cat in a place it shouldn't be, the cat gets a quick squirt. Obviously, be careful where you squirt in the studio..but otherwise, have at it. It's actually tons of fun..and really drives home the point.
If none of this works, try getting an actual tree-stump or something. The only thing cats love to scratch more than furniture is wood..
...and if STILL nothing works, consider giving your cat away. Just DON'T declaw him/her. He/she depends on you for food and safety...without you, he/she depends on those claws.