Stay away from Copenhagen snuff. It's too fine and too dry. You can use pretty much any other long cut brand. Even grab a tasty cherry or peach flavor. Something with lot's of juice. Mix them together for cheech.
The matter comes down to how accurate you can spit. A sloppy spitter is going to have a lot of juice where she misses. If you leave too long a trail you will wind up with tobacco juice all over your plants. However you feel about spitting on your plants, the nicotine is a 'natural' poison for insects. Not just people.
The juice will dry and crust. The crust will block the light. The more you spit, the more you'll cover the holes. Spit high, at first. Let the brown juice run down and crust over holes below.
Try not to swallow the juice. It tastes nasty and is a little slimy going down. Keep it off your clothes. If you get some on and don't know it, you'll have a crusty spot. And for we men of the Brotherhood of the Beard, don't get it in your beard. I hear it's hell to get out of your hair.