Pandora informed me that Armors wouldn't be allowed, because they do not show on the actual character. Headgears do, including lower gears like tails, as long as it falls in Upper, Mid or Lower Headgear it will be allowed. It has to be a visible sprite.
Also, you don't have to test it, you also don't need a test server to use it. You can just rename your sprite to an existing one, put it in the data folder and look it up in game. You'll see the new sprite but others will see the normal one.