The great challenge was making the grid fin small enough while detailed enough.  .4 line width with .4 nozzle couldn't make it look enough like a grid fin.  .2 line width with a .2 nozzle was the most realistic.

It was the 2nd lifetime print with the .2 nozzle.  Helas, the .2 nozzle would require thicker walls to be a structural piece instead of an art piece.  Unsolvable problems with leaking of the .2 nozzle prevented it from printing any more than .5mm walls.

The best results with the .4 nozzle used .3 line width.  47mm wide seemed to be the largest practical back scratcher.  Either the grid fin would have to be larger or compromises would have to be made.  It would be a good application of resin printing.

The latest practice has been to glue the scratching head on the handle.  There has never been a need to swap scratching heads.

A bit of hypersonic entry phase in every scratch.