Load Trainable Weka Segmentation classifier without image?

I’m a complete fiji beginner, so I apologize in advance for any stupid questions.
I have written a macro which opens n files as a stack and then applies a TWS classifier. The processing of each image in the stack takes about 1.3min, that’s fine, but the loading of a very small classifier takes 10min. Unfortunately I cant’t process all images at once, because imageJ runs out of memory (already added more memory), and also because the cell moves and the images need to be cropped differently after some time. Is there any way to open the classifier without an image, and then add images to it?
Can anyone help? Thanks!