Hey Maxim!
Thank you very much for your suggestion. Unfortunately our "project" still uses 1.13.3 (as of today only 1.13.3 is available via stretch-backports), so the mirror module (>= 1.13.4) is not yet available for here.
I hope I will find the time to eventually report back on your config suggestion this as soon as I have the option to run your configuration with "live conditions".
I very much appreciate there is an official implementation for "replaying requests" now. Keep on rocking!
Best
Benny