Hello and welcome Gayle,
the Tokyo guys that use straps mostly play the Hammond 44 which has attachments for a guitar strap. I modified a wooden MyLodica that way and some time ago I equipped my Vibrandoneon with accordion straps, but that’s quite difficult with a plastic melodica. I noticed that my Hohner Fire has the same sort of eye at its back as your Hohner Performer, and I was able to attach a key chain with a karabine. Maybe that’ll help…
Greetings, Quetscher