This is now incorrect I believe. Before the t map changes dark guardians always dropped a map every kill random between lvl 1-4. After the changes to maps they now simply sometimes drop a map like every other creature that drops em. I will check ea to confirm though.
Yeah due to the fact that UO literally just changed their T-Map system a few months ago, and we are now using this new system, we will need to test on UO ourselves, regardless of what anyone "swears". A video would be a great help though.
The UOGuide article posted was last updated in 2009. That is way out of date regardless and we would not use that source blindly without testing.
Yes it should be just stash and supply now. The old map system they dropped lvl 1-3 so with the new system it should be stash and supply. I'm not sure how much rng is involved with the amount of stash vs supply.