Thanks for the further information!
Yes I totally agree with the shimmer/luster part----it is always ALL or NONE.... so I already gave up trying to control or predict it and just let the outcome surprise me every time.
And the bottle.... I was too amazed by the exquisite design that I failed to notice how inconvenient that narrow rim was.
Now I prefer more practical bottles such as that of Sailor Jentle Inks and Private Reserve.
My suggestion is to buy one of Goulets empty bottles on sale and once all the ink is out of it and it's cleaned, use it for filling. If you like purple, you could just buy Levenger Amethyst ink from Amazon for $6 delivered. it has the plastic cone inside for easy filling of pens, is fairly resistant to tipping, and is a beautiful clear bottle. Another good option is to use a wide necked crafting bottle and a cork but not as secure or portable. Anyway, glad the information could be of some help. I did find you get much more consistant shimmer if you use a good wet pen, and are sure to swirl the pen or shake it to get the shimmer to agitate into immulsion. if you have a good pen that writes wet but doesn't drip or splatter the inside of it's cap, just shaking the pen up and down like when you'd drum the eraser of a pencil on the desk can really help. If you're using a eyedropper pen, ceat and add one of those little plastix beads shaped like a WWII Beach spike or even a cheap bb or Airsoft pellet to the inside to help keep the shimmer in immulsion. just make sure whatever you use is substantially smaller than the pen body and NOT lead or something that will break down in the ink or release particles to jam the feed.