Merchanting clans ALL fail. Learn how to merchant/invest solo, I'll be releasing a new copy of my Ultimate Grand Exchange Investing Guide soon - you will make much more then if you just did what someone else told you to.
Yes the people at top make a good bit of money as they buy the item days before and sell far before the "goal price". It's best to stay away from merch clans unless you know when to sell the item that's being merched.