Here is a video from Honer with Steve Baker giving instructions on reed gaping
I have this tool and works great for lowering gaps of the reeds. Very easy to use and very easy to over do it as well. Be more gentle on brass reeds than steel reeds.
Just finished gaping some reeds on my Baby Fat harp. Got to say the E-Z gap tool is the easiest way to gap reeds on a harp that I have found so far. Much easier than trying to bend the reeds down by poking at the tip.