Hell Meph can drop all set amulets and the expected split of them is
1 Tal Rasha's
1 Telling of Beads
per 7 of each of the 6 others.
If you manage to get 45 set ammies by Saturday, that's about the numbers you should have.
Meph can also drop all unique amulets, with the expected split
3 Seraph Hymn
10 Mahim Oak Curio
20 Nokozan Relic
per 5 of each of the 8 others.
If you find 75 unique ammies, that's about the numbers you should have.
1/117 of Meph's drops will be rings, and 1/235 will be amulets.
In a 3-players game (ie enough to make him drop 6 items every time) that means he'll drop a ring about every 20 kills and an amulet every 39.
About 1/12 of those that he drops will be unique, with 0 MF. With reasonable MF you can get that up to about 1/5. That's still quite a lot of runs for each unique.
Andariel is only level 75 so she can't drop Mara's or Metalgrid, Nature's Peace or Wisp Projector. She can drop all set rings and amulets.