Thanks, appreciation is mutual. It's good to share what I've learned and give back :thumb_up:
Depends on the amount of Bark you start with and the size of the (pans/double boil containers) you use, but the idea is to make sure it is covered for the duration, until reduction.
A normal 500ml pan, with say 20g Bark, 300ml of water will be a good amount to start with. You WILL need to top this up maybe half way through the boil. You could use an indefinite amount of water.. as nothing will be lost except the water. Though it's wise to use a minimal to moderate amount though, otherwise reducing the volume will take forever!
Oh- if you're double boiling, half fill the pan (can be any pan) with water, place a piece of folded paper at the bottom to act as a buffer, otherwise the glass bottom of your jar touching the metal of the pan directly, could crack it (It happened to me).
If you are not double boiling and using the pans directly, make sure they are stainless steal, not aluminium or even teflon coated, because this could get into the mix once acidified, and you definitely don't need aluminium in your Huasca!
There's no rule of thumb, because there's too many variables, like what heat, size of pan, volume of material, volume of water, ambient temperature etc. It's easy to judge though. Just make sure when SIMMERING, the amount of water/solution doesn't get too little, as this will BURN and DESTROY the plant material and spice, and possibly evaporate most of it out! Unless you want to lick the good stuff off the walls and ceiling

lol
Yes, you can save it for a good few weeks in the fridge, and indefinitely in the freezer.
Edit: Extra note- It's easy to deionise/filter your tap water. Boil it up, let cool, pour through tight filter, let settle in an open top container for a day or two, this isn't distilled water, but it's as clean as you're gping to get it without distillation :thumb_up:
No worries with the questions, it's best to ask. And it gives me a chance to revise! And a chance for anybody else with any tweaks to jump in :thumb_up: