How are Lens Flares Blended?

I am trying to make a rainbow effect that can be viewed up close, like on a wall of mist on a sunny day. Here I’ve made a post process material:


The texture is a very saturated circular gradient. The material is only using a simple additive blend.
Here is the same texture being used as the ‘shape’ of the default post process lens flare effect:

As you can see it looks pretty good, especially the largest flare on the left. Most importantly, the colors are entirely different, and look a lot more natural. When I change colors under the ‘Tints’ array, nothing seems to happen, so I don’t think they’re having any affect. Any clues as to what is actually being done to blend the texture, or how I can replicate the effect?

I think the tints are broken sometimes. There was a bug when projects that were converted from legacy version were corrupted. And that made tints not to work. Try to make a new project and test them there.