Resident Evil 4: How to make a big move in mercenary mode?

Generally, personal unique skill is a close attack when the enemy is hard and straight (head or feet or flashing lights will make the enemy hard and straight). Klaus (the strong man with little red riding hood) can press F to be oversized, but he can only use it once in a while. I think HUNK's twist is the best way to kill difficult monsters such as chainsaws.