Best practice for building in Cospaces

I’ve begun to move from noob to beginner with much of the Cospaces bulding, except moving around in create mode.
Added a considerable number of images, only to view and find everything has shifted because the main model (gallery) moved. I did have it locked thanks to advice here.

But in locking images to display boards, I must have unlocked th main model.
Has anyone got advice to ensure a whole heap of work isn’t undone when I’m on a short timeframe for delivery?