One of the key strategies we did many years ago was to spouse split to my wife's member account as I was the higher income earner.
It took 12 years (approx) contributing 85% (15% goes to the tax man) of all my yearly super contributions to my wife to get both balances similar.
We have a SMSF so in my opinion it was much easier to do (and no fees) as we are both trustees & members - from memory all we did was put it in the minutes and wrote some letters from myself as a member to both of us as trustees about the contributions, and filled out the ATO forms. All the paperwork then went to the accountant for the tax return and financial statement preparation (for prev FY).
We only did the splitting contribution once per year (for the previous year), but the important thing is that it can NOT be done (or undone) years later in one bulk contribution - there is only a 1 year window after the end of a financial year to perform this.
