Well, I'm using Unity 5.4, Playmaker 1.8.3 and I tried ArrayMaker 1.1.5 which resulted in lots of compiler errors and my project not running anymore.
I was going to use it for a simple inventory but it looks like I'll have to find a way around it...
EDIT: I just tried it on my PC at work with the same versions (well, Unity 5.3.x) and it works. Guess I'll have to try some trickery tonight...