I have still yet to master them! It takes a combo of top watering in phases(top water each a little for two rounds), do something else in the grow for the water to settle out, do another round of top watering, do something else, and then add water in the tray until it stops taking it all up in 15min. I use a Solo cup to dish out the water in the tray and usually two rounds is enough and check the memory weight to see if a third round is needed. Actually I check the memory weight often during the process. That using 3,5 and 7 gal bags. 10gal and up, it's 15min rule for the most part.
I do think it is VERY important to use some sort of surfactant extract to help with even watering and help prevent dry pockets. I use ThermX70. It was what Jeremy of BAS was using at the time. I still have an easy year supply left. It's a VERY dense product and a little goes a long way. The weight of the bottle does stand out for sure.
I'm just not sold on their dry down properties. I'm pretty sure it's because of my watering. I've got a fair bit invested in them, so I need to try and master them.
In the foreseeable future, I'm really only going to use the 3gal bags for seed making and last min strain testing. At this point in time, all future grows wll be in Earthboxes. When I get my growroom built, I will probally go to some sort of automated watering system. If I flood out there, no big deal. I'm not doing that in the house.
Gotta go check to see if the last girl popped!