I was debating where to put this because it's a lot of pictures but not really a review. But anyway, the spouse procured a bottle of Diamine Golden Oasis, a shimmer ink. This is not really my shade of green and shimmer inks are also not my jam, but I did some writing on different papers to test it out in my FPR Himalaya ultra flex pen and thought I'd share it here. As stated in the written part, I shook the bottle gently before inking the pen, and I agitated the pen by gently rolling my wrist about every two lines for all of its. I get the feeling the gold particles settle in this ink particularly fast so if you're not vigorous about agitating them, you can reduce the glitter and see more of the green. And also probably clog your pen up a bit more, haha.
Card stock, 100 bristol I think:
Leuchtturm 1917, but it's an old model book with the rougher pages: