Personally I know re-x loses quite a bit from the weight, but it doesn't mean that some DMT won't be removed too. Also some of the "impurities" might be psychoactive(which would explain the slight difference between yellow and white spice effects).

I have at least equally powerful experiences with both orange and white spice, sometimes the orange/yellow one seems to have even more powerful effects(weird realistic factor).
I believe though that there is also very orange spice that can have lots of impurities in it, therefore having less powerful effects.

I'm going to start repeating the RE-X steps on the brown/gold waxy, left over substance to try to get more out of it I think. Or at least try to get yellow spice out of it. Because I've just been discarding it. I shouldn't be so so wasteful with this stuff, as if it was a tv dinner. Note to self, do not throw away dmt.

Anyway, I still haven't used any dmt since this "I thought I died" business happened. I'm still afraid actually to retry it. Is this normal, and is the only way to get over this, to just force myself to do it again...like a leap of faith type situation?

Never force yourself to anything, do it only from free will when you feel ready. Just start with low dose and you'll be fine. 10-15mg.