Okay I managed to get the result I want by using a blendspace instead of an aimOffset and changing the additive type from mesh to local. But aim offset should work too. I can’t get the aim offsets to work with apply additive, so I’ll probably just convert everything to blendspaces.
UE4 has great documentation, but there are a few problems like this which go unanswered indefinitely. Hopefully someone who understands AimOffsets can share their knowledge.