Ok, ambidextrous is the ability to use each hand with equal skill in a task, such as writing. What is the term for using different hands for different tasks unrelated or similar but not always with equal skill? For example, writing and throwing a baseball with the right hand, but using a cash register/calculator (using the 10 key method) or playing lawn bowling with the left, but not able to do so with equal skill with the opposite hand.
I believe that’s actually called being ambidextrous as well.
I started a similar thread a couple of months ago and a couple of posters said the term for this is “cross-dominant.”
I would have gone with “heterodextrous” but that doesn’t appear to be a word, at least not according to the dictionary. It is out there, though.
As are a lot of words in this language. 
I thought the thread title was referring to us clumsy types.