Trackmate: cells of different sizes and saving issues

Hi everyone. I’m new to Trackmate and I have a few questions. Is there a way to generate tracks on the same image sequence for cells that are different sizes? There is only one way to input the diameter, but what should I do if I want to generate tracks for cells of widely different diameters?

Additionally, after I save my work on Trackmate and create an xml file, when I try to reopen the Trackmate file I get this message: “Problem reading the settings; cannot find image file name in xml file, the source image is not loaded; cannot instantiates spot analyzers”. My images are saved as TIFFs and part of the image name is located in the xml file, so I am not sure what is causing this issue.

Thank you!