"Basting" is just another fancy word for pre-injecting. Ignore the advice not to brine if it is in solution (basted, in a salt solution, as yours says). I have been brining such turkeys for 20 years, and they have never been too salty. The pre-injection is no substitute for the slow osmosis process of brining. Also, it is all about achieving equilibrium. Brining will balance the salt between the brine and the bird, so it won't necessarily add that much salt, since the pre-injection is not actually that salty. If you are worried about saltiness, then reduce the salt in the brine by 25%. Turkey breast in particular is not terribly flavorful on it's own. Plus, you will likely be using it in a sandwich, etc. So it needs to be on the salty side to balance out the other sandwich ingredients. Think about how salty deli turkey is. There is a reason for that.