I don't have a cat tree but I did add a platform to the top of one of my 30-inch scratching posts and put a table between the 2 posts. That way they can look out the window. As far as scratching goes, some cats are very picky about carpet types. The 2 posts I got came from online but my boys didn't like the type of carpet that was on them (cut pile or shag). I knew they loved the loopy type carpet so I covered both posts in this material and they use the posts exclusively now- no scratching on furniture. I have a wavy scratcher board that has some sisal on it, but they seem to like the carpet or cardboard types better.

I'm sure that your cats will like laying and playing on the tree, but the scratch-ability is kinda up to them. If it was me I'd get a few cheap scratching posts with different materials on them before I spent a big wad of money on a tree...if scratching is the main issue for its purchase. But that's just me... and I'm cheap, LOL