Here you can see a photo of the mask (minus its straps). The large squat tubular form of the attached canister is quite common, and strictly functional. Given that the horn nose has a strong fantasy element to it, I think that the canister balances it nicely by keeping the simpler shape.

Of course I will gussy it up some, giving it a real Victorian look with leather, and decorative reliefs, etc. Beautiful yet functional. That is the plan for now, always subject to change. Above is my sketch that I'll work from.