If needed, you can add clamp-on DT bosses to a frame without using an adapter such as;
http://www.niagaracycle.com/categori...8-28-6mm-black

Once you are comfortable riding in the drops of the bars, DT shifters work well because they require no movement of your body core to reach down and shift (unlike stem shifters which require shifting weight up/back to comfortably reach).