Here is a cool tool you just have to get. This is a Knipex Plier Wrench. It works like a combination channel lock, crescent wrench, and ratchet. You adjust the opening by pushing the button, and then clamp with hand pressure.

This tool is ideal for working where a standard crescent is too bulky or thick, and a channel lock does not have the grip power you need.

You can order these in various sizes from most tool suppliers. Googling "Knipex" will get you a bunch of websites to check.