Okay I have an r6 rig with r15 bones but for some reason it will not properly import into Roblox. Here is an image of the blender window:
Here is a video of it working perfectly in blender:
Here is a screenshot of what it looks like in the studio animator:
(Also for some reason it refuses to scale to the real size of a character)
In case you were wondering it took me like four hours to make this once I figured out how to do it. Weight* painting is very annoying.