This worked for me last night, though it took probably close to an hour to set up and get working.
Things I've learned over that hour .
* The Mole crickets are everywhere, but should not harm this. I did dig a bunch of holes though to course where I wanted the tarantulas to spawn, and it worked very well.
* The Wharf Roaches will stop tarantulas from spawning! Scare them away if you notice the ground beetles and tarantulas stop spawning. And of course, scare away the beatles.
I was able to bring home 28 Tarantulas. I've unlocked the 40-inventory slots today, so next time I do this I'll be able to catch 38 Tarantulas. I should also hopefully get started faster next time. When I first started, I thought the mole crickets were a problem, but it turns out it was the wharf roaches. I spent most of the hour digging hundreds of holes and stopping every mole cricket I could find.
I used a spare room in my house to store all the Tarantulas. Will sell them to the bug man (Don't remember his name right now)