I went through and tried to find monsters around the same defence and HP as Moss Giants that were undead.
Here’s what I found.
Moss Giants for reference: 60 hp 30 defence
Tortured Souls release with Ecto early 2005.
(51/38)
Skogres release 2005.
(71/35)
Shades will be released before Salve amulet and are aggressive.
(38/26)
(56/42)
These skeletons can be found in the wilderness, near Sinister cheat, Edgeville Dungeon (wilderness), and on Crandor.
(59/36)
They are the only monsters on this list with “armour” stats. They have -2 crush +9 stab and +11 slash. It would likely be advised to use a crush weapon if you notice a difference in accuracy.
Nice research. Salve ammy will be a pretty big buff to combat rates. I know they weren’t very consistent about applying its effect to every undead monster though, and I think OSRS was later updated to cover more monsters, so it’s hard to say for sure that every monster you expect will be covered.
Also, whip comes out not long after salve ammy so at that point it’ll probably be worth waiting for whip too. Whip + salve is when combat rates will really go through the roof.