Its pretty expensive stuff, you have to use multiple units depending on the size of the trunk. You also have to apply it when the tree flowers and reapply each year. That also means you are drilling into the tree each year, I am not sure but I think when using this type of injection system you sould only use every other year and in a different location.
I take down alot of gum trees because the customer is tired of raking up the balls.
The only instance we've used snipper in the past is for the sweetgums. We tried it in a couple different ways. Either on it's own, or w/ a foliar app. of florel. However, results were mixed. The thing is there is only a few day window of when to apply. You may show up and be too early only to have to come back or vice versa. Either way it is a gamble, and not really a cheap one either.