I wondered whether there was a connection between cacography and the expression 'cack-handed', but it seems not
Do you know, it seems to me there IS. Look at Dubdub's opening post, where she says "cacography, poor spelling and/or handwriting". Now look at yours where you said, "Cack-handed: ... 2. Awkward; clumsy".

We had a fascinating discussion here a long time ago about left-handedness and the (perceived) implications of being so, even the very word sinistral; mostly centered around its being the opposite of right.