I also use a main diet of small crickets, besides that, they prefer other small prey over larger ones.
Here they are used to be eating crickets as a main food source, wich i gutload and supplement, waxworms, small grasshoppers etc.
I do keep them well ventilated and rather dry in times.
When i do so, they hide theirselfs in the branches and go out in the evening/night to burry theirselfs in the soil.
This i do keep somewhat moist, so they can still regulate their water levels.
In some of the hollow cork branches i put in some moist moss as well.
After the dry period, i give them a wetter period in wich i let the water feature in front rise.
I noticed they are quit adapted to swimming as well.
I make usage of UV lights, and i do see them taking advantage of this,
they often go and sit in the rays for a while, after wich they will retreat in their cork bark again.
For the easyness of keeping them, i must say, getting them healthy after import can be difficult.
Maybe it depends on the exporter and importer what shape you'll get them in.
After they are asteblished, i must agree, they aren't that easy to stress anymore.
The only thing is they often scratch their noses against something.
No offence, but i think the viv of 20 gal is quit small for these frogs.
Especially since they are easily around 3-3,5 inch each.
If i am right, a 20 gallon tank high is 24" x 12" x 16".
I used to quarantaine them in a 52 gallon viv i believe, altough i am not used to measure in gallons.
The viv was 90x50x50 cm (35x20x20 inch) and it went ok.
But now i put them in their final terrarium, i notice a huge difference in behavior.
I think these toads need to be properly housed since they tend to move lots around the space they have available.
I now house them (7) in a 150x65x130cm (60x26x51 inch) or 335 gallon tank.
About the breeding of reptile depot i did not know.
The breeding attempt as written in Reptiles, i do know off, i also mailed with the author, but i got the same reply i got from the zoo in Europe that bred them.
Difficult to raise the tads to toadlets, and high mortality with the toadlets as well.
I to experienced this mortality rate to be extremely high, i think the critical stage lies around 6-9 months.
After that period i didn't loose any more of them.
I'll try to mail with Steve Busch then to see what things he did different,
maybe i can see what makes it easy for him to raise a large amount and keep them in large amount strong and going from clutch to adults.
I was already planning to try again, since i cycled them again and 3 of the females are getting gravid again.
Like you said, the males will go girl crazy a lot, that is true, but having them in amplex isn't the difficult part.
Just like all toads, getting the eggs is the tricky part
In my experience they do need the cycle to get gravid, i use a dry/hot period followed by a colder/wet period in wich i heavily feed, that seems to be working best for me.
I don't see and hear much from them when it is dry and warm (30-32 degrees C)
but as soon as it is getting wetter the males will start chasing the girls.
Can it be that the little ventilation is a trigger in you're case? Cooling down at night, getting the humidity up ?