I have some experience with Slime so I thought I would mention this, as it MIGHT relate to tractor tires...
My experience relates to...don't laugh too hard now...bicycle tires. I commuted by bicycle year round to work for about five years until the plant closed and I retired. Since it was 16 miles each way I preferred not to have to stop and fix punctures, expecially in the dark/cold/wet times...
Bicycle tires use tubes, and perhaps it had something to do with the tube moving within the tire, but I would eventually end up with a flat, because the slime only worked so long. I think it may have had something to do with the tube moving inside of the tire, and whatever it was that caused the puncture to begin with, being still in the tire, continued to reopen the hole in the tube.
I finally gave up on slime, since I learned I would eventually be getting a flat anyway, usually while on the road, and it was just as easy to change/fix the tube one time as the other.
What I am leading to is that if it were me, I would not put a tube into a tire I was planning on using slime in. I think what you might end up with is a situation similar to what I experienced with my bicycle tires. Better just to put slime in the tubless tire, and let it seal around whaterve punctures the tire, if that thing stays in the tire, or to just fill the puncture hole if only the hole remains after the puncture occurs.
Just a bit of unrelated experience that may relate, for whatever it is worth... /forums/images/graemlins/grin.gif