I seriously doubt most home producers around the world wait until a full moon before they produce any? But if that suits you, then fine.
The particles will be small enough regardless of what condition the moon is in, make it anytime you want.
If it's home produced and people use common sense and not drink it by the bucket full a day for an extended amount of time then nobody will 'turn blue' as you put it. It's NOT Colloidal Silver one makes at home if using LVDC to produce it, it's a predominantly ionic silver product, and I have yet to find an authoritative publication stating home produced predominantly ionic silver solutions to have created any cosmetic issue.