Is there a price list available (maybe as PDF)?
Is tracked shipping (for the much higher price, respectively) available? For getting the ordered parts in reasonable time the price is not the biggest issue for me.

Tbh, I am not really happy to order some parts via email and hope for the best…

If you know someone who sells ready-to-use barium sulfate based paint to consumers, I would appreciate it.
I can only work with the things I have access to.

I suspect that the accuracy and repeatability of the luxmeter plays more of a role here than the coating of the sphere. In the worst case, we’re talking about an 8-9 percent difference here (which means not the same amount of difference in light flux), which certainly has an influence, but I still don’t consider it to be that significant.

What difference should be expected there? Without a comparison value, I can hardly evaluate any differences…