Circle Packing with Variable Radii Inside a Boundary

Grasshopper/Kangaroo Wizards:

My task at hand is to design a vent for a transformer. As a new user to grasshopper, I try to incorporate it more and more into what I do as a way to learn new things by applying them. So for this case, I'd like to pack circles of a particular set of diameters inside a curve boundary and if possible, group larger circles around a point within that space (transformer's "hot spot"). I managed to pack fixed diameter circles inside the boundary but haven't figured out how to choose from a list of diameters or pool the larger diameter circles (most likely through an attractor point script?) around the hot spot. Any help would be appreciated. Attached is a concept sketch, model, and current definition.