My usual design would be to use your main scarab beads in the center of the necklace, with smaller, more neutral spacers. Then you can use smaller, similar colored beads and the same spacers for the rest of the necklace.

OR find a larger focal bead or pendant for the center, and use the scarab beads on both side evenly, again with smaller neutral spacer beads.

What I've found focuses attention on the larger beads is this patter: several small found beads, a flat disc/heishi (glass or metal), larger bead, another flat disc/heishi, and several small round neutral beads. Repeat.

Hth!