@Mutedog Unfortunate, maybe it'll work later.
I mainly used this site as a source: https://culinarybite.com/articles/guide-making-kvass-using-sourdough-starter

What I changed is I added the sugar to the hot water to fully disolve it and quantities ×1.5 because it better fits the bottles I'm going to use.
For flavourings, I just threw in a bunch of stuff and I'll adjust in the future from there. Cinnamon, ginger, cloves, black pepper, koriander seeds, juniper berries & tiny bit of salt.
Once bottled, I'll add some lemon juice to raise acidity.