It's a nice airframe to start with. I use 8 x 4.5 propellers with 3S battery.
Here are the settings for the control loops:
<!-- config F450 with 8"4.5 propellers-->
<!-- command laws/ stabilisation parameters / gain-->
<airframe>
<section name="STABILIZATION_RATE" prefix="STABILIZATION_RATE_">
<define name="SP_MAX_P" value="9600"/>
<define name="SP_MAX_Q" value="9600"/>
<define name="SP_MAX_R" value="9600"/>
<define name="GAIN_P" value="400"/>
<define name="GAIN_Q" value="400"/> <!-- NOT TESTED -->
<define name="GAIN_R" value="350"/>
</section>
<section name="STABILIZATION_ATTITUDE" prefix="STABILIZATION_ATTITUDE_">
<!-- setpoints -->
<define name="SP_MAX_PHI" value="40." unit="deg"/>
<define name="SP_MAX_THETA" value="40." unit="deg"/>
<define name="SP_MAX_R" value="90." unit="deg/s"/>
<define name="DEADBAND_R" value="250"/>
<!-- reference -->
<define name="REF_OMEGA_P" value="720" unit="deg/s"/> <!--divide by 360 to obtain bandwidth in Hz (2Hz) -->
<define name="REF_ZETA_P" value="0.9"/> <!--1.2 -->
<define name="REF_MAX_P" value="90." unit="deg/s"/> <!-- maximum angular rate reference -->
<define name="REF_MAX_PDOT" value="RadOfDeg(8000.)"/> <!-- maximum angular acceleration reference -->
<define name="REF_OMEGA_Q" value="720" unit="deg/s"/>
<define name="REF_ZETA_Q" value="0.9"/> <!--1.2-->
<define name="REF_MAX_Q" value="90." unit="deg/s"/>
<define name="REF_MAX_QDOT" value="RadOfDeg(8000.)"/>
<define name="REF_OMEGA_R" value="360" unit="deg/s"/><!--was720-->
<define name="REF_ZETA_R" value="0.9"/> <!--1.2-->
<define name="REF_MAX_R" value="90." unit="deg/s"/>
<define name="REF_MAX_RDOT" value="RadOfDeg(1800.)"/>
<!-- feedback -->
<define name="PHI_PGAIN" value="1000"/> <!--1000-->
<define name="PHI_DGAIN" value="450"/> <!--500-->
<define name="PHI_IGAIN" value="50"/> <!--400-->
<define name="THETA_PGAIN" value="1000"/> <!--1000-->
<define name="THETA_DGAIN" value="450"/> <!--500-->
<define name="THETA_IGAIN" value="50"/> <!--400-->
<define name="PSI_PGAIN" value="2000"/>
<define name="PSI_DGAIN" value="1000"/>
<define name="PSI_IGAIN" value="300"/>
<!-- feedforward -->
<define name="PHI_DDGAIN" value="0"/>
<define name="THETA_DDGAIN" value="0"/>
<define name="PSI_DDGAIN" value="100"/>
</section>
<section name="GUIDANCE_H" prefix="GUIDANCE_H_">
<define name="USE_REF" value="1"/> <!-- Use Reference Generator -->
<define name="REF_MAX_SPEED" value="4"/> <!--reference generator max speed -->
<define name="REF_MAX_ACCEL" value="1.0"/> <!--reference generator max acceleration-->
<define name="REF_OMEGA" value="RadOfDeg(18.)"/> <!-- reference generator bandwidth, divide by 360 to obtain bandwidth in Hz (0.05Hz) -->
<define name="REF_ZETA" value="0.9"/> <!-- reference generator damping-->
<define name="MAX_BANK" value="35" unit="deg"/> <!--max bank setpoint-->
<define name="PGAIN" value="80"/> <!--90/65/90/30 -->
<define name="DGAIN" value="120"/> <!--90/120/70 -->
<define name="IGAIN" value="20"/><!--10/20-->
</section>
<section name="GUIDANCE_V" prefix="GUIDANCE_V_">
<define name="REF_OMEGA" value="RadOfDeg(36.)"/> <!--reference generator bandwidth, (0.1Hz)-->
<define name="REF_TAU" value="1"/> <!--(0.25) constante de temps générateur de consignes Vz-->
<define name="MIN_ERR_Z" value="POS_BFP_OF_REAL(-3.)"/> <!-- (was -10) altitude error saturation-->
<define name="MAX_ERR_Z" value="POS_BFP_OF_REAL( 3.)"/> <!-- (was 10) altitude error saturation-->
<define name="MIN_ERR_ZD" value="SPEED_BFP_OF_REAL(-3.)"/> <!-- (was -10) vz error saturation-->
<define name="MAX_ERR_ZD" value="SPEED_BFP_OF_REAL( 3.)"/> <!-- (was 10) vz error saturation-->
<define name="MAX_SUM_ERR" value="2000000"/>
<define name="REF_MIN_ZDD" value="-1"/> <!-- (was -3) reference generator min acceleration--->
<define name="REF_MAX_ZDD" value=" 1"/> <!-- (was 3) reference generator max acceleration--->
<define name="REF_MIN_ZD" value="-3"/> <!--(was -1.5)reference generator min speed--->
<define name="REF_MAX_ZD" value=" 3"/> <!-- (was 1.5)reference generator max speed--->
<define name="HOVER_KP" value="120"/> <!--100-->
<define name="HOVER_KD" value="80"/> <!--70-->
<define name="HOVER_KI" value="10"/>
<!-- 1.5m/s for full stick : BOOZ_SPEED_I_OF_F(1.5) / (MAX_PPRZ/2) -->
<define name="RC_CLIMB_COEF" value ="163"/>
<!-- BOOZ_SPEED_I_OF_F(1.5) * 20% -->
<define name="RC_CLIMB_DEAD_BAND" value ="160000"/>
<define name="ADAPT_INITIAL_HOVER_THROTTLE" value ="0.5"/>
</section>