If anyone happens to have the same issue: use the file name as variable. That complicates somewhat the code in resurrect-prologue.g (you need to check for each possible file name if that file exists and recreate the associated variable(s) instead of just executing it), but shortens the string significantly:
M913 X0 U0 Y0 Z40 E0:0 echo >{""r""^global.Modus} G91 M83 G1 Z1 F12000
(I added "r" as a bit of luxury to place the file close to "resurrect.g", since the variable only consists of a number in my case. Using only the variable gives you six precious characters more)