The following description is specifically for an Graflex using an 89Saber Graflex Kit and a custom electronics and chassis system.
Solder header pins. Clip the excess on the bottom side. Further sanding to remove excess is preferable preferable.
Start by trimming down the contacts and mounts on the battery holder to not exceed the thickness of the PCB. Solder the battery holder.
Solder the spring loaded contacts to their PCBs.
90 degree solder joints.
Mount the Teensy combination board and solder.