In the end it's up to you and no amount of the right research is going to persuade or dissuade you.

I believe that it is not necessary for a child to be on solids before six months... My child did not begin to consume them to be of any benefit until almost 9 months of age. So regardless of any research I am not about to start my children on solids at 4 months. I will do it when I believe they are ready and when I am ready. They don't need the food. "Food is FUN until I am one" sentiment ...

This is not to say that someone else' child won't react to solids differntly, or that when they choose to start solids should change - just that the research i choose to peruse and believe backs up my choice. And if the research helps you sleep at night when you introduce solids at 5months instead of six in the hanging hope your baby will begin to sleep at night - that's your choice