Soft Claws/Paws Sizing

I'm ordering some soft claws online, but am not sure of the size to get. Here is what the webste says:
Guidelines:

Kitten (approx 1-5 lb)

Small (approx 6-8 lb)

Medium (approx 9-13 lb)

Large (approx 14+ lb and over)

Marishka is just about 9 pounds, but has a smallish frame. I'm just not sure if it changes the size of her paws enough to warrant going small or medium. I tried holding one of her toes up against a picture sizing chart that another website has, but that was kind of impossible with her...heh. Any idea?
Thanks : )

you need to go with Medium. It is best to go closer with weight. Also- it is better to order a size up if you're not sure than a size lower.

My Sweetie weights about 7# so if I get Sort Paws I would get her the small. My question to all of you is : do these things really work? I have two cats, Juno uses her scratching equipment but Sweetie prefers furniture and I can't break her of the habit. I can buy these at the local Petco or Petsmart. Your comments and advice would really be helpful.