Hello Anna,
Whatever you do of course will be perfect for you, but here’s my $.02 on the Iodine:
1. I think it would be better to use Organic Iodine derived from Kelp or other seaweed, if possible, or even use the seaweed itself in your Plasterite (I’ll bet you’ll *really* want that Champa in there if you do 
)
2. Another source for natural Organic Iodine is Black Walnut Hulls
I use Lugol’s 5% too, but it can be very styptic beyond a certain point, at least it is to me; To broadcast an Iodine vibration, my personal opinion is to use an Organic sourced form of Iodine which I think would be safer across-the-board.
Thank you for making and posting your very beautiful geode 
. Do you feel the difference when running your hand across the geode opening? I’ll bet you do . Very cool .
OH! BTW if you *can* feel the diff at the opening, then congratulations on having invented the first directional Plasterite 
, you should be able to focus it directionally, just like a Ham radio antenna, by orienting its position
Namaste,
Linda 