Why do people keep saying you need 'full buffs' to make Acolytes worth it? You can easily get them up to 3s to hit and 4s to wound simply by having 30 of them with -2 and D3 damage. The only worry is that they might not be fast enough to get fully in range of what they want to kill. Even then, they're going to kill whatever they attack regardless.
Same 6+ save plague monks have, hardly any work when rolling. They're simply hard to obtain, but things like this (Scroll down to the priests) and this (They're not even hiding who they're marketing these to) exist if you don't want to convert?
I think they're pretty solid. They will absolutely hurt anything they touch and are great to have around in case the fiends get focused down. Just skitterleap the engineer to the acolytes and buff them instead! I think an alternate is to simply have a second engineer nearby? List I'm going to be putting together around march when that second link starts selling again:
Warpseer
Bell
Rocket Rat
x3x20 Clan Rats
x6 Stormfiends
x30 Acolytes
Bridge
Leaves 20 spare points which I could switch over to a second engineer for redundancy I think. In case the bombardier dies or vice versa.
