You can change the slope and output scaling using the circuit in Figure 55 (Rev D datasheet) along with equation 15 on the next page. Decide on the desired slope that you want (200 mV/dB). Then pick a reasonable value for the R2 Resistor (say 2K).. Then plug these two values (Sd=200, R2=2K) into equation 15 and a value for R1 will come out.
If you want to change Vtgt, use a resistor divider between Vref and Vtgt (there are components on the eval board for doing this). I recommend a Vtgt of 0.625 V