They do need to be wired in a balanced manner. Only method #3 at
correctly interconnecting multiple twelve volt batteries will work well.
Others may say it doesn't matter--but unless there is a compelling reason to not optimize charging and discharging why not do it the best possible way?
Here is a video of 3 twelve volt batteries that have been wired in an unbalanced manner for 2 years. They have been equalized. The test shows how CCA has been adversely affected.
unbalanced for 2 years