Inquiry about Customized Plastic Ring Whistle

I am looking for a customized version of a plastic ring whistle. The design needs to have both mouthpieces positioned right next to each other so that wearing the mouthpiece on the outside of my pointer finger does not press the other mouthpiece against my middle finger and cause irritation, and also so that both tones can be blown simultaneously. I am interested in an initial batch of 10 pieces, but I may consider a larger quantity if required for the customization. I would also like to know if it is possible to produce a few of these in silver, with the same customized design. The size I wear is 20.5mm. I look forward to learning about the feasibility and any related details.