Ahh, thinking about it, I think I have the short version then, and one of each...
One is from a spartan lite:
And one from a clear frame mag swiss champ, which I think has the weird tang you mentioned.
I'll take a look at the two opener spring approach, but what about springs that don't have back tools? Ideally it'll look neater than me making a filler (although like I said, if I have to...)