The trade federation army wasn't the big for two reasons. The Republic didn't have a standing army at all, and the merchants would have built the smallest army that suited their needs. Second, the trade federation group was setup to fail, the whole point of the sucession was to give Darth Sidius a reason to raise an army for the Republic.
The math the bothered me was the time line. The clones growth was roughly doubled, which means they where growing for 10 years roughly. But if Dooku / Tyrannis was already evil 10 years ago when he setup the clone army then it would have been around the time of the first movie and violated the "there can only be two dark jedi" rule.
Jay