Hi. What is the best closure system for watertightness in a simple rucksack/daypack? Is the drawstring main compartment with a "storm flap" over it of the classic rucksack better than the simpler zipper on the more civilian daypacks?

I would like to have suggestions for affordable daypacks. Do you know by any chance what is the model Michel Blomgren uses in his videos:



(Here he uses the drawstring to fasten his GI poncho to a tree to make a lean-to shelter. I guess one could replace the string with 550lb paracord)

I'm not sure about a Maxpedition bags, they are a bit too complex and tactical for my taste and not readily available in stores and not inexpensive either.

Thanks