Is there a certain formula I can use to DCA into bitcoin?

I am trying to have a good method and strategy to invest into bitcoin, it goes something like this

I set a buy limit of bitcoin price of x, to where I will invest 100% or y, of my designated weekly allocation towards bitcoin crypto. If bitcoin drops 2% for example, I will increase my investment to 110% for example. And if it goes up 2% I will drop it to 90%.

Now this is all hypothetical but I was wondering if there is an already established formula or strategy like this out where I can use it to more effectively invest in rather than relying on strictly guessing.