Happy Saturday,
Simon when you import them back into EA studios you don’t lose the magic number unless you export it again (just dump the collections when you’re done looking at the strategies by pressing the trash can at the top right corner). The magic number will just stay the same. When you upload and put all the EA’s for the pair into the portfolio you can see the contents (if you select the correlations in options it’ll display equity line and trading rules correlations) as they currently are running in your MT5, and then you can see their performance as an aggregate portfolio when you are in the “summary” tab.
To Andi’s point you can just sit on the collection for a few months and then re-upload them. But for me, i like to have them in demo so i know they are acting on the correct market structure before i put them live. This also helps me track their performance without bias. So at the end of the day you get to create your own “style” in work flow :)