The 3-d drawings for the sustainer and its cross-section view can be found below.
Figure 1: Sustainer.
Figure 2: Cross-section view of the sustainer.
Here, the thrust curve for the sustainer can be found.
Figure 3: Sustainer thrust curve.
This is an M1329 motor, with a total impulse of 5.8 kNs.
The average pressure is 660 psi with a peak pressure of 825 psi.
With a mass of 6.5 lbs, the propellant contributes to more than 49% of the mass of the whole motor, which is 13.22 lbs.
Lastly, the expansion ratio for our booster is 19.75.
For reference, the motor simulation file can be found here: 5.8KNs_M1300_24in.ric