How do I export to a media with fewer than 10 fps (audio+video)?

Hello, I see lots of discussion on how to work with odd framerate and the "Posterize Time" effect. I have a slightly different question which seems to not show up in searches: "How do I export to a media with fewer than 10 fps?"

I am editing on-line classes where the lecturer writes on iPad. It is handwritng and there is no need to see smooth writing, so I thought I can spare on the file size by lowering the media fps. Indeed going from 24fps to 10fps I can still get a 30% smaller file. I was hoping to go down to 1 or 2 fps, which still give acceptable experience for the viewer in my opinion. Indeed I tested the resutl with the Posterize Time effecrt and turns out OK-ish. It's a bit uglier, true, but makes the lectures tens of Mb instead of 1 Gb each , and this helps students behind slow internet connections.

So I would like to ask how to export to a media using less than 10 fps. H264 seems to not accept less than 10 fps in the export media window and other formats are even less flexible, or lack the audio (e.g. TIFF).

Any suggestion on how to export to a media a less than 10 fps including audio?

Best

Roberto