Well one of the ways I do this is as follows. Build the file you want for your set and then link your character into that file from your character file. I use a group and set the duplic group appropriately. Then you can scale the group instance to what you want. After you have that scaled, then proxy your rig and you should be happy. Otherwise, if you try to scale a rigged mesh you will find it messes up. The only way I have been able to do it is to delete the rig, scale the mesh, bring rigify back in and start from scratch. That is why I link it in - no mess, no problem. Then you can link in your animations as actions to the same file and all should be good.