DFWII, Low and slow isn't required for turkey as it isn't a cantacerous(sp?) tough cut like a butt or brisket that needs time to tenderize. Slowing the cooking time can add to drying, so if you can get the temp higher, that's good but not essential.
BTW-Most commercially available turkey breasts are prebrined (will say injected/packed in a solution of xx% of ......) that means its brined. Additional brining really isn't necessary for moisture. If you're using it as a means to carry in some extra flavor and it's worked for you in the past, stick with what you're comfortable with.