Hello PomPom
We're going through the process of applying now, medicals and Police checks next next. Without any children, making the decision was easier for us that it obviously is for you. This may sound like a silly idea but it's worked for me in the past.
Let fate decide and toss a coin!
When a difficult and life changing decision needs to be made, taking a long time over making the decision only makes it more difficult. Plus I always find that in the second or so the coin is in the air, I know in my heart which side I want it to land on.
Good luck and I hope you make the right choice for you and your family.