Originally Posted by FBinNY

The HS wrench might work or not. If the cup is tight an open end wrench of this type isn't rigid enough and will flex open and slip, or worse could crack and you'll be punching the crank.

For less than the cost of a headset wrench or BB chasing tool, neither of which assures success, you could buy a pair of Jacobs Chuck removal wrenches and have the crank off in 10 seconds with little effort, and no damage to anything. I've been suggesting these for people in your situation for 30 years, and AFAIK, no one who every tried a pair failed to remove their crank.