I'm not 100% sure what the glycerine does TBH. I just saw others were using it.
I found this recipe recently,
https://github.com/seyDoggy/biopolymer-recipe/blob/main/recipes/gelatine/gelatine-v1_1.md
A fair bit of research seems to have gone in to it so once my corn syrup arrives (can't get it as easily in the UK) I'll have go and see if it's better.