I did longer testing. In 8h (+1min), with all the kill switches in use (phone as idle as possible), using the suspend preview, battery went from 98% to 70%. This gives much more accurate picture of the potential of the suspend feature - huge possibilities compared to current usetime (even if ~2,25%/hour isn’t very efficient - still no optimization yet)! Several times more than the previous estimate based on two hours (although the setup was different too).
Like in previous test, L5 clock alarm did not wake me up, but that’s why we have backup systems. Interestingly, it started to ring immediately when I pushed power button to wake the phone, as the wake-up ring event was still in progress [made me wonder: who woke up who…? 
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