To add to this guide. Get your calculator out and make sure that anything you add doesn't shoot up at +12 or overpower other similar items e.g
555360 11 200 196 196 0 0 0 2 0
555360 12 200 9999 999 0 0 0 2 0
If you are going to do this properly look at the other items specifically 2handers for this example. And look at "roughly" how much they go up by each time. Say a halbert goes up at 103 max atk and 97 min atk. Then take this as your base and make your items do something similar.
e.g
555360 1 200 78 64 0 0 0 2 0
555360 2 200 181 161 0 0 0 2 0
555360 3 200 284 258 0 0 0 2 0
555360 4 200 387 355 0 0 0 2 0
This will help the server in many ways. The main way being that the weapon will not be overpowered.
Sorry if you don't understand this that well I wanna get to bed

Will clean it up when I wake up unless someone else does it. lol