I had about 60-80 weapons in my bags and it kept using a certain few. I don't know why it picked the ones it did, but it never picked any other weapon.
As Akoroth said, it only works with weapons in your default backpack, so you could have a total of 16 varieties, no more.
Originally Posted by Baracuda
Oh that's nasty ^^ If they fix transmog for polearms then only use of this glyph will be staves for 2h and daggers/fists for 1h.
Doesn't work with Fist weapons, much to my profound disappointment. It does have a few other uses though.
You can sheath weapons on your back you normally couldn't sheath there with a unique combination of transmog and the glyph. A guildmate of mine says he enjoys using this in combination with a brewfest stein, allowing it to display on his back. It
It also does allow you to glyphmog weapons you normally couldn't glyph, such as fishing poles, those unique PVP weapons, white and grey quality weapons, and those select few non-legendary but non-transmogrifiable weapons like the Shadow's Edge.
It does need some serious work though, because it reverting back to base weapon when the buff falls off, or your weapon going back to it's normal transmog when going through a loading screen is so profoundly frustrating I've given up on the glyph all together.