1st....find a groomer who will clip his nails, it should be cheaper.

2nd.....don't keep the scratching post by his window, put it as close to where he LIKES to scratch as possible. I have the plain post types DIRECTLY in front of a favorite sofa corner.

The double sticky tape works, and you can hardly even see it once it is in place.

Good luck because declawing might save your couch but may just get you an even worse problem later.