I like it, you have a great idea there. Besides using different color peppers, I'd think about sifting out the smaller pieces through a screen and just cast the whole ones.
Yes the Brass was put in after it was turned to size.(A little larger than the bushings actually).All the larger peppercorns had pits in the middle of them.
It is cast in Alumilite.To my surprise the peppercorns did not float.I filled the mold about 3/4 full expecting them to float.When they did'nt float it was a mad rush to get more peppercorns in the mold.