If I set BOINC Manager to only work after idle for at least X minutes...then when my screensaver kicks in, nothing happens, it says "no running tasks, computing suspended by user".

So apparently I have to set the Manager to "run always"? Then at least the screensaver works properly.

This is dumb/annoying. So every time I enter the Manager to do anything, I'm forced to have it start working immediately?

I only want to use the Manager for setting prefs and messing around with configs, not actual work. I only want the screensaver for doing actual work. Apparently this is not possible to setup that way?

Set your preferences to start crunching one minute before the screen saver kicks off, or set your screen saver to kick off one minute later than your crunching. If you set both to the same time, they sort of conflict with each other.

Alternatively, if you wait long enough, BOINC still start crunching eventually and you won't see the "no tasks running" message on the screen saver.