Armature / Single Bones = OPACITY ?

https://giphy.com/gifs/dUHYdvCB0NhmyKtssU Hey All,

I'm sorry if this feature is already exist in 2.8 beta, I'm asking since I'm not sure it's also a suggestion:

Can I change the Opacity of the Armature to 25% or 33% or whatever I like? All I see on the tab is IN-FRONT which is ON / OFF toggle but I would like to have more control and tweak specific bones transparent in specific level, or the all armature at once.

I probably missed it somewhere since I'm still learning Blender 2.8 but if there is no such option next to "IN-FRONT" it will be harder to tweak while working.

Sorry about my bad English and thanks ahead!