i personally would use a spider sire & a dam pastel yb.
because, by the time they are both ready for breeding. You could hope to produce a male Bumblebelly, which you will holdback (spider+pastel+yb)
by the next year, you could use that male bumblebelly breed back to the mother. (male just need a year to mature, and female take 2-3 years, here you dont have to wait as the mum is already mature) and nail the killer jewel killerbee ivory (spider+pastel+pastel+yb+yb).