Yesterday I used some honey to glue 18x24 cm film to cardboard, that was put in the plate holder where the glass goes. (Others have reported using jam with success.) Worked fine, except that my 1980-s Tasma film seems to be fogged. (If I am not still using it backwards...) If you don't get the film to stick to the cardboard/glass whatever you use, it might get trashed by the darkslide.
The prewash washed the honey away just fine...

/matti