I use an Echo with bicycle handlebars and a harness. I looked at the Kombi but all they had was the single handle type.
If you want to use herbicides I would cut for a while, then treat the stumps with a sprayer; preferably in spring or early summer while the nutrients are in the stem.
If you want to use herbicides I would cut for a while, then treat the stumps with a sprayer; preferably in spring or early summer while the nutrients are in the stem.