I'd recommend against using a Global Source; GS are always-active and using resources. The only bits that should be set as Global are webcams and video capture devices... actual hardware that needs to be started/shut down between each scene change otherwise.
I just set up a 'master scene' as a template at this point; set every element up in relation to each other, then copy it however many times I need and delete the stuff I don't need from each of the copies. Keeps the elements in place when swapping between them. A bit of a hassle, but when you have your scenes set up, editing them (aside from adding a new splash screen here and there) doesn't tend to happen on a daily (or weekly, possibly even monthly) basis.