Control of plasma H:D isotope mix using solely shallow pellets (in H or D) was demonstrated in recent experiments, attaining ~50%:50% ratio. The isotope mix propagates from the edge to the core on the confinement timescale. Isotope dependence of energy confinement is within error bar to scaling laws. A dataset is collected for different pellet sizes, isotope content and plasma current, and including for the first time pellets with ITER-like ablation and relative pellet size. Data indicate high ablation efficiency for pellets with ablation depth r/a<0.95, but falling sharply for shallower pellet deposition.