I simply do the loading as recommended by Leica et al. The thread comes up every six months so here is my previous answer . . . 😉
"Trimming the leader helps avoid getting the edge caught in the gate/pressure-plate and then tearing or jamming. The Leica (and Zorki) recommended method involves simply having the film cut correctly - this works fine without removing the lens or farting about with cards etc. The card included with early cameras was, according to the instruction booklet with my camera, intended for exposure notes and can indeed often be found covered in smudged pencil marks.
As you drop in the take-up spool and wiggle the cassette in to place, turn the take-up spool slightly backwards (towards the cassette) so that the springiness of the film lifts it over the sprockets. Doing that makes it completely painless.
The actual film trimming is conveniently done with a pair of small nail-scissors and for the twenty perforation measurement you can check which of your fingers is the correct length, or put a couple of pen marks on the case, or tiny bits of tape as markers inside the baseplate etcetera, etcetera. Simple to do when you have a working method organised, but there is perhaps a 'shock' reaction at first . . . "
