It really depends on how many cages you have . If you have one cage a pump in the mid 100s will more than suffice , Even 64 gph would do . Now if you have 5 cages like jdog, one in the 300 gph range will be good .
Yeah pond pumps are low pressure but if we really want to recreate their environment do you think rain in madagascar or yemen is a "fine mist"? Nope its small droplets or drizzle like the rest of the world and regular pond pumps create that effect . Am not saying the "fine mist"doesnt look...
What I did is use a 10 gallon tank with a screen cover and use that same egg carton that comes with the crickets . Works great for me I have over 1000 crickets in there with no problem