Speaker setup in 'music' surround modes? Rectangle or circle?

I’m starting a project where I need to mix an art installation in hexaphonic surround, all speakers equidistant from the center aka 6 speakers in a circle. However, I’m a bit confused by the VST Multipanner graphics. The panner shows me the speakers (L, R, Ls, Rs, Lr Rr) set up in a rectangle setting. I was wondering what the relationship was of that graphic to the panning/deconding.

I need a panner for an equidistant (circle) setup. I seem to remember that a long time ago, I could find a VST multipanner that showed me the speakers in a circle in music mode. (EDIT: this was in cubase 7.5 or so).

So is it just the graphic that is rectangle and is it decoded to a circle setup (all speakers equidistant from the center). Or does the panning/decoding expexts me to have the speakers in a rectangle setup?

Next to the VST multipanner, I’ll also use the Harpex plugin, which decodes all music modes to equidistant speakers. (but Harpex only accepts ambisonic inputs, and I’ll also need to pan mono and stereo sources).

Thanks in advance for any answers!

You might have seen it in “Anymix Pro” which is an included alternate panner you can use. I have no idea what the difference is in practice though between the panners as far as how signals are adjusted.