I was feeling really stuck on how to build the canister. The primary problem in my mind was getting it to fit with the look of the eyepieces and horn. Those two are both strong designs with little subtlety and no detail.
I decided that while I could keep the basic bulky shape of the canister, that I would need to build it from scratch (and not simply modify the original one), in a manner similar to the nose horn, and in the same material. Here is the acrylic and resin model, and the engraved bottom part (made of acrylic and Bondo™), which will be attached before molding and casting.