Sorry, i have no experience from other DAS scrubbers other than the one i am using now so i have difficulties giving recommandations. I can just tell you how mine scrubber is: i am using 1cm between the holes, the scrubber was made to take 4 screens so it has 5 holes in spraybar and the holes is precisely align between the screens and on the outer sides. The holes in the spraybar is 1,5 cm, i tested also 2,5cm size holes, but 1,5 was better mfor mine scrubber.The pump is labeled 450 liter pr hour but it is regulated down almost to the minimum, i think it is importent to have good pressure in the spraybar.
You have to test some different setups, any changes in the scrubber box design will need different pump, spraybar holes and so on.
Jnad