There's a quick approach for a 5.(1).2 spherical setup in a 5.1.4 frame (see ZIP in the attachment). You'll have to open in a 5.1.4 channel. The .2 top layer channels will be routed to top front and rears, but you can easily change that yourself if your DAW support 5.1.2 directly (Nuendo doesn't). I included a screenshot to illustrate the idea.
The VMO-file (for Vienna MIR Output) in the ZIP goes to MIR 3D's "Output Formats" folder (C:\Users\[YOURNAME]\AppData\Local\VSL\Vienna MIR Pro 3D\OutputFormats under Windows, or Library/Application Support/VS/Vienna MIR Pro/Output Formats on MacOs).
Personally I don't like this format a lot, to be honest. It's quite remarkable how big the loss of spaciousness is compared to 5.1.4. 😊
5.(1).2-MIR_3D_HOA_(5.1.4frame).vmo.zip-1696259642033-z57nv.zip/Dietz - Vienna Symphonic Library