[PaleMelanesian]

Resonance is entirely dependent on length and not related to diameter. I'm thinking of how a brass wind instrument works. There are student models with a narrow bore (easier to play) and professional models with a large bore (requires stronger lungs but makes better and louder tone). The both make the same pitch, but the volume and quality of that note are different. I think you want the lower frequency here, which would require a longer pipe. If it gets too long you get restriction so you'll want to go fatter as well. I doubt you're going to run into that limitation here, though.