If I move something close enough to my face it appears in view twice seemingly semi-transparent

That sounds like what I experience, not just for things very close to my face, whenever my eyes are aligned to something in front or behind.

But in order to do the dominant eye test, you need to only see one image in the foreground and background simultaneously. So how does that happen unless the view from one eye is at least partially supressed?

This is one of those things that's really hard to talk about and describe, but I would love to actually understand it. Also no, I can't notice my blind spots.