I use allways 1-4 on black keys and 1-5 on white ones. With rare, very rare exceptions.
I like 1/3 in some places, but I recently read of someone who permanently injured their hand by playing octaves with 1/3. So watch out!Ian
JamesS, isn't this supposed to be an etude in legato playing in octaves? Why then am I supposed to practise staccato?