"didn't know how easy, or PRACTICAL it would be to find complementary notes on the other side"

You need to get yourself a chart of the button layout - then just look at it to check where the notes you want on the other sides are.

I personally wouldn't recommend using the restricted two finger approach - it will cause to to waste time, when you find you have to 'unlearn' bad habits. Those who try the two finger method on a Stradella Bass on the Piano Accordion regret how restricted a style they have backed themselves into - and it takes ages to start off again 'properly'.