You do know you usually do it the other way around, right?
You usually first decide the data you need and then build the app and do the hardware estimation . Hardware should not be leading.
Even if you want to do it following your approach, it will depend on the characteristics of the data how much space the app will take into memory. After that it would depend on the complexity of your dashboards and selections your end-users are going to make what would be the "optimum".
I suggest you first go find out what is wrong with your app (as in Qlik Sense we do not create any reports) before bothering with this "optimum memory" question .
let me explain, the app here in question is developed by some one else and I am trying to publish it on the Qlik server.
Ideally importing an app and publishing it, should work fine. But for some reason, when I import this particular app, it does not contain any sheets once the app is imported or published on the server.
However, opening it locally works fine.
So on your local client it does show data, yet when you import it to the server and publish it to a Stream, the app does not show or does the app show but have no content?
If it has content locally and exactly the same app does not show anything on the server, my guess would be Security Rules or Section Access. Start with checking the Audit option and see if it comes up with any fancy security rules related to the app or parts of the app. Next, check for "section access" in the script, usually at the start.
Here is what I found:
Test server version (2.2.4)
Prod server version (2.1.1)
Local Qlik sense desktop version (2.2.4)
When I open apps in the local desktop version and then try to import them on prod, I see this issue.
Most probably this is related to the difference in the software versions.
I tested importing the app using an older desktop version, it worked fine.