I can't find any information specific to a P. viridis only brew so I'll pose another question here.

The brew has separated after sitting in the fridge for three days with particulate settling at the bottom. Should I decant and discard the matter or will that decrease potency, in which case, brew should just be mixed before reheating?

Thank you.

I'd get rid of the sediment, the goodies are all water soluble anyway

In theory the alkaloids should be in the solution.. But when you decant, there's always some water left over in the precipitates at the bottom, so what you could do is decant/filter, and then run a bit of warm (acidic, ideally) water to pick up more alkaloids that may be trapped there.

You can also save the decanted stuff somewhere and keep it just in case, and maybe in the future if the effects are low, you can try extracting from them or whatever.