The overall design is based on pictures of the Dutch version of the gun, the smaller details are based on detailed photos of the Czech 7.5 cm kanon PL vz. 37 and the 1 picture from the Netherlands Institute of Military History” This was done as I could not find enough detailed pictures of the Dutch version. The gun was also used by Finland, Italy, Germany and Czechoslovakia.
Test printed on an Anycubic Mono SE in 0.05mm layer using Anycubic Basic Resin. The Spandau M.25 is a delicate model, might be best printed with a more flexible resin.
I have added files with support for resin printing, those worked fine for me. Feel free to use those files, but remember those are tuned to print good on my own printer. So might be better to add your own support based on the experience with your own 3D-resin-printer.