I have a lot of cactus and mesquite that causes real problems with the tires on my equipment. The fillers generally sold in auto parts stores are not highly respected by people in the tire business. There is one brand I researched called Genseal but I'm having trouble getting them to sell it to me. Any other recommendations would be appreciated.
I don't know anything about Genseal.
I've always used "Slime". I know, it's one of the auto store products but it's almost always worked for me. I don't pay any attention to the quantities it says to use on the jug. I pour in 2 or 3 times that amount. I reckon that in a tractor I'm not going to be going fast enough to cause any instability.
Also, many years ago when I worked in New Mexico, the surveyors ran through cactus and mesquite that an armadillo wouldn't venture into. They all ran at least 10-ply tires on their trucks. They did ride a little rough on the road but they didn't get stuck in the middle of nowhere trying to fix a flat. Now, I know that my Kubotas both came with 6-ply Titans so whenever it comes time to replace them, I upgrade to 10-plys. So far I've got all the front tires on 2 tractors done and they're all filled with slime ... just in case.
If I lived and worked in that kind of country, I'd seriously look into having my tires foam filled. It's expensive but it's a lot easier on the back, especially at my advanced time of life.