Well, been doing the tires, still have some sanity left, but it really does get me crossed eyed, so I can only do it in short sessions.
The first thing I did was glue the tires together, and then sand off the existing molded tread.
As you can see, I used .20x.30 plastic strip to lay out the new pattern, going from one side lug to the other side lug, but one lug lower. Trying to glue just half the strip in place. I then let everything dry.
I then did the same thing for the other side, trying to run that side to an imaginary intersection of the other lug. Again trying to glue only one side, and again I let this dry.
I then clipped off the excess ends, and ran my knife along the center line of the plastic tire then had to pick out some of the strips that had too much glue on them, The then ran some MEK into each section for a more permanent bond.
After letting them dry one more time I took my sanding strip, and smoothed and rounded the edges to the sidewall lugs, and sanded the tread so they were even.
I still have to do the little rounded conection between the lugs, and I'm sure it will become another cross eye adventure. But that will be the next installment, along with changing the hole pattern.