I don't screen my dirt. I use chunks and all unless they are huge, then I just pick them out. I think it's just a matter of choice if you want to screen or not but honestly I never saw a difference so I stopped doing it ages ago.
I just add in the amount of soil I want which is usually 1-1/2" unless the tank is small, then moisten the soil and compact it with my hand to get any air pockets out. Next I carefully add my cap which is also 1-1/2". That's it. I place a plate or bowl on the cap and let the tank fill very very slowly so as not to disturb the cap. Hook up the filter and let it run for 24 hours. After that I drain the tank by 1/2, plant heavily (80%), refill, and that's it. If you put enough plants in you don't usually have any high ammonia spikes as the plants use the ammonia as well as nitrates.