What I'd suggest to do (I got this tip from someone else!) is to add a master anchor point to your pngtuberplus model and make everything a child of it.
Then just adjust the position offset of the anchor so that the head is visible nearer to the center point. That way you don't have to go and readjust everything.
And actually, come to think the thing I just posted in another thread might be useful for your purposes too. I wrote a utility for rescaling pngptuberplus models because I got annoyed at how much of a pain rescaling stuff could be after the fact. given you pretty much have to go in and manually adjust the entire rig.
