Which things in the manuscript can be dated?

[Koen G]

I think you are right with (maybe) the exception of the zodiac month names, I would put them nearer to the middle of the 15th c., not that it matters much

Maybe it doesn't matter much, but it's still interesting. In the "later writing" we have Germanic, perhaps Latin (portas..?) and French.  Do their scripts belong to different periods? How precisely can those be dated? Do they overlap? The more precisely we can date these things, the stronger statements we can make.

For example: between ... and ... inscriptions are in Germanic and Latin. Between ... and ..., the MS was held by someone who wrote in a Romance dialect. Between .. and .. someone added page numbers. And so on.