Third Hand with spot for PCB Vise, it uses 6 third hands and a vise for the build along with 6 1/2-20 nuts. I would recommend getting some little stick on feet for the bottom to provide some friction since the 3D print is smooth and slides easily.

Third hands: (https://www.banggood.com/6Pcs-RJX-RJX1627RJX1545-Flexible-Universal-Soldering-Arm-Joint-Pipe-for-Soldering-Base-Station-p-1548937.html?rmmds=myorder&ID=229&cur_warehouse=CN)

Vise: (https://www.banggood.com/Mini-Carving-Bench-Clamp-Micro-Hand-Carving-Clip-Tool-p-1027925.html?rmmds=myorder&cur_warehouse=CN)