Hey! I know you from reddit DIYBeauty sub. Remember their rules? No DIY sunscreen? That’s because you will never be able to make sunscreen at home.
Sunscreen works by creating an even layer on your skin. It is not about the filters, solubilizers or high content of the filters, it is about even distribution of nano particles. Some filters are in nano form and not really solubilized, but distributed/dispersed so well and even that you think they are dissolved. For this you need really high end equipment and knowledge.
So drop this idea and buy one.