This is a remix of Make Anything's Guitar Wall Mount Hanger with Flexible Top to add support for MultiBoard via MultiConnect. This is available in 50mm, 56mm, and 60mm versions depending on the neck width of your guitar.
For printing use 100% infill for the arm and use TPU for the padding. Use the default orientation. No support or brims needed.
For mounting onto Multiboard, use 2 Big Thread MultiConnect Connectors with one space in between. Then just slide the arm in place. The padding should friction fit, but can be glued in place if needed.
My print settings: Printer: Bambu Lab P1S Nozzle: 0.4mm Stainless Plate: Textured PEI Filament: Arm - Bambu PLA Basic Black, Padding - Sunlu 95A TPU Black Layer Height: 0.2mm Wall Loops: Arm - 2, Padding - 3 Infill: Arm - 100% Rectilinear, Padding - 15% Grid TPU Temps: Nozzle - 208C, Bed - 50C Dried TPU for 8hrs at 55C All other settings are default to Bambu Studio 1.10