I've done BS breasts before, no issues. They didn't get very brown though, but yours may since you're rubbing them. You can also "reverse sear" them to brown them up some. I didn't rub them, but I hit them with a brine for 1 hour and it was awesome tasty -- very tender and juicy.
Here's the brine that I used:
1 gallon water
3/4 cup kosher salt
2/3 cup sugar
3/4 cup soy sauce
1 teaspoon each of dried tarragon, thyme, black pepper
1/4 cup olive oil
Start by boiling the water and then adding the salt and sugar, so that it will dissolve easier. Then add the spices to the hot liquid so that the flavors are extracted. Cool the brine solution.
Place the brine solution into a non-reactive container and immerse the chicken in the brine, weighting it down if necessary. (Use a heavy plate or a brick inside a ziploc bag as a weight). Place the container into the refrigerator and leave for 10 hours*. You can also brine the chicken in an ice chest, by pouring the brine solution into the ice chest, immersing the chicken and weighting down. (Use ziploc bags filled with ice cubes, or "blue ice" to keep the brining solution cool during the brining process.
Upon completion of the brining time remove the chicken from the brine and wash twice for at least 30 seconds in fresh water. Dry the chicken with paper towels.
*NOTE: only 1 hour for breasts, not 10