Two questions about filleting edges on this tire

I have this very basic tire tread I’ve created. You can see how it gradually slopes and converges to the tire hole.

I’d like to run a variable fillet from a value of around 0.040 to a value of basically 0.0. I have two problems:

  1. I can’t actually input a value of 0 on those bottom handles, so I’m unsure how to actually make a fillet that gradually reduces to zero.

  2. Even if I use the same value of 0.040 everywhere, obviously there’s a real problem here because of the way the edges intersect.

Here is my file:

Tire.3dm (2.1 MB)

What’s the best process for creating this sort of variable fillet that converges to a point?

Hello - FilletSrf the red to the blue:

Trim later…