Importing Scratch projects

I understand that this can seem a little bit old. I have several large Scratch 1.4 projects (more than 200MB) that I need to move to Snap in order to use Snap as the platform for my course of this year instead of Scratch 1.4.

First I tried to import the projects in ypr format. The problem is that, whereas all the scripts are correctly imported, the images are not all correctly imported and the sounds are not imported at all.

I also tried to convert the Scratch 1.4 projects with snapin8r or to save the projects in Scratch 2 format and convert them with snapin8r2. The problem is that some of them are too big for Scratch 2, so I can't export them in Scratch 2 format and convert them, and some them instead are not correctly converted by snapin8r or snapin8r2 for what concerns the images and the sounds.

Is there a correct way of moving large Scratch 1.4 projects to Snap? Or does someone know which are the limitations of Snap ypr import (or of snapin8r/snapin8r2) so that I can try to complete the import/conversion functions?

Thanks in advance for any help.