First things first, give your stand a try w/ all figures you desire to use it with.  For some reason, some of the stands, work perfectly without modification.  However, in our experience, the vast majority will require the following to be used with Armada Unicron:


Step 1:
On each end, in this region of the stand pole, apply a small amount of super glue.

Step 2:
Smooth the liquid glue out all the way around the diameter of this portion of the stand pole, again on each end.
Step 3:
Depending on your intention, you can insert stand pole into the stand's base on top portion before drying for a permanent set. 

OR, IF allow the glue to dry thoroughly (very thoroughly) before connecting, you may be able to continue to interchange the 3 stand poles included and still get a tight enough fit w/ the black stand pole to function w/ Unicron.


Step 5:
AFTER superglue is thoroughly dry, (be sure to allow at least a few hours for the superglue to dry completely!!!)  you are set to try.

For the best balancing of the toy on the toy on the stand, have Unicron facing forward w/ the wring BEHIND the stand pole as shown in the picture on the right >>>

Step 5 alternate:
The Unicron toy can balance on the stand with the planet ring in front of the stand pole, but ONLY when glued in our experience, as shown in the picture to the right.  >>> 
As you can see, the stand does tend to bend a little more as seen in this picture.  If the stand pole is securely glued to the base and top, this will work fine on a stable surface.  But exercise caution!  We are not responsible for any broken Unicrons from it falling off its stand.

Good luck!