Might be a little more work, but could you cut what you wanted first, then spray?
I've tried that and it's not any more work than the other method . Just seems like (IME) that they tend to spread less if you kill before cutting . I'll try using more Remedy on the stump and see if that works .
Locusts are a beach
but they're a really hard wood ( like Bois d'arc) useful for fence posts , furniture , etc. Have to be careful and let 'em dry out for a couple of years when using on a fence , though . A "fresh" post can sprout a new tree .