That'll work or try this...
Stand the wheel up, apply the freewheel removal tool and then secure it, but not too tight, with your QR lever. then take a long pipe and stick your ratchet or wrench in the end of it and use the pipe to apply leverage to remove your freewheel. Don't forget about the QR and take it off before completely unthreading the freewheel. Or you could stick the freewheel in a vise and then turn the wheel like a bus driver turns his steering wheel, basically using the wheel as the wrench.