Tangent circles of different radii

Hello, i'm new to kangaroo, so sorry for probably lame question.

I try to do a tangent circle packing with circles of different radii in particular form.

1.For the first step I want to understand how to make circles tangent to each other and to boundary

2.For the second step I want to add a galapagos to find optimal amount and sizes for circles

I take Daniel Piker's kangaroo 2 example with tangent circles of one radius(what I want to archive is the same picture but with circles of different radii):

I tried to make circles with different  radii. But distance between centers of the circles is  equal, no matter what radius length is.  And collision with the borders is also very strange:

Could anyone give me a hint on how to make circles of different radii tangent between each other and with the borders