I installed the plugin and use the given conditions.
I notice I use 9 small water catcher by now for 1 sprinkler and it's still not enough to keep it running continiously.

Any advices to how I should set the config to have it easier and maybe like only need 4 small catcher for 1 sprinkler and 1 large catcher for 1 sprinkler?

  "Add Amount Of Water To Water Catchers": 10.0,
  "Add Water To Water Catchers Every X Seconds": 20.0​

I would presume you could set this so that your water catchers are filled up every second. Maybe add 1000ml every 10 seconds??

I don't get what the difference between these two lines might be.

I've never used this mod before.

It'll add (magically) extra water to all your water catchers every x seconds. So 10, 20 would be add 10 extra mL of water every 20 seconds. Maybe a 1000mL every 10 seconds? You could probably do away with your water pumps if you had it set a certain way. 

I think this will work for your 'perpetual water cycle system'.

Aah got it. Thank you.
So these 2 lines do the same the Water Catcher Boost Plugin does, right?

I think so. The developer of that mod uses the term Boost a lot on that page. "Boost is used but never defined". Let's presume it's water.

Yeah. I guess it's the amount of water the water catcher fills up with in time.
So, for me, the same as in these 2 lines here.
I could get rid of Water Catcher Boost then.
Will try it out.
Thank you for your help.