1956 Penny doubled die

[KurtS]

Here's an Australian Penny which I've tentatively identified as a doubled die reverse, although I'm unsure which doubling type this may be. 

There are a few interesting details, such as where the "doubled tops of STR (see photo) are nicely aligned, yet there's a dramatic offset at the bottoms of the letters.
Perhaps the tops are only MD? I particularly like that ghost K above the designer's K.G    

[triggersmob]

Wow. Nice Perth penny.
That doubling is very interesting.
Let us know if you find out more about it.

[KurtS]

Thanks Steve--and here are the results of more research. At the suggestion of an Aussie error collector, I made an overlay to test whether this was caused by clashing dies. Confirming his findings, I see the obverse legend is simply is in the wrong location to create such marks from a clash. I'm more than ever convinced this is a doubled die.

On a technical note,  I re-shot the coin to ensure the scale between obverse/reverse was very close. Fortunately, two denticles almost exactly align obv/rev, which really helps the accuracy. 



Obverse as reference for devices:

[KurtS]

Judging from the last overlay, a die clash seems unlikely, but what about a doubled die? Can an overlay reasonably predict the positions of these secondary features? 
To that end, I've created one more overlay using the same reverse photo without speculating on distortions which may happen in a double-hubbing.
Here the secondary reverse image simply rotates around a common axis.
On this new overlay, I see many consistencies to the marks on this coin. []  Keep in mind that secondary marks are doubled too.




Compare how the image above predicts the doubling seen here: