I couldn't find a "backrack" for RC scale models so I created this one. It's 110mm wide and designed for 1/16th scale, but could be scaled to 1/10th when scaling it to 160%. (I haven't tested this)

Pictured is the backrack sitting on the Dodge Ram Late 80s model attached to a WPL chassis.

Print Settings

On a 0.4mm nozzle machine, set your external perimeter to 0.25mm. 
On a 0.25mm nozzle or smaller machine, the default settings should work.

See slicer picture for how the sliced backrack should look like: you'll want at least two perimeters for the thin portion of the frame.