For the no-droop operation, start with R2/R1 ratio between 1 to 3. Choose R1 between 400Ω and 800Ω, then adjust R2. Final value of R2 may need several iterations in order to put the crossover frequency, fc, in the right place/value. With no droop, add capacitor C2 in series with R2 according to Equation 11 on page 24 of the DS.