I would try multiple products but go cheap for now. Each person is unique and you will have to find the right combination of products and hair care routine that your hair requires at each length.

I believe it depends on diet and what goes into the body too. Drink lots of water.

You might find it necessary to wash everyday at that length until you reach a point when you have great 2nd day and even 3rd day hair with no washing or styling.

There's no silver bullet that works for everyone for instance currently my hair is loving silicones but I might hit a peak next month where I look like crap using the products that work now.