I would try adding some isopods to the 29. They will supply a second food source for your leuc and reduce his dependency on ff's.
I used to do the typical banana slices/fruit but I found that using babyfood is easier to store/put into the tank. I just take a spoonful and dump it in water bottle caps and place it in the viv... the azureus like this but not so much with the leuc who prefers hiding in a mess of rabbits foot fern.Try some banana slices to keep your ff in a concentrated area. Also, make sure you have some springtails in there. Those, the small isopods, and the banana station should offer him plenty of food to find. As far as smaller tanks. I don't really know. I have a group of 4 Costa Rican auratus in a 30 gal breeding. I have a pair of azureus in a ten gallon breeding. And another pair of azureus in an 18x18x24 exo breeding. So, those are all smaller tanks to me. Obviously not too small in my opinion. I have a pair of cobalts in a 20h, that have only laid one clutch in 6 months. I don't think tank size matters all that much, as long as it's big enough for the number of frogs in there.
Baby food. That's a novel idea. I actually don't do the feeding stations in my vivs since all my frogs are adults and don't have trouble depleting my microfauna, and hunting for flies. As far as isopods, I go to Buy live pet insect tarantula, spider, millipede, centipede, and pet bugs. They sell a variety of smaller isos. I like the jungle micropods. They're small enough for pretty much any frog to eat (except maybe thumbs) and they produce well in the vivs. I also bought one of the larger types so I could guarantee to always have isopods in there to break down debri and eat the vitamin powder that gets in the cage. Occasionally I have to go through and kill/pull some of the larger ones, as breeding can get out of hand if the frogs don't find the young ones quick.I used to do the typical banana slices/fruit but I found that using babyfood is easier to store/put into the tank. I just take a spoonful and dump it in water bottle caps and place it in the viv... the azureus like this but not so much with the leuc who prefers hiding in a mess of rabbits foot fern.
I used to have springtails in both my tanks but I'm not really sure what really happened to them, they just don't seem to be their anymore I really should introduce them again, any other isos to put in? I heard of people trying roly-polies before...
As for the frogs eating each others eggs I have actually never thought of this... I'll keep an I eye out now just in case- thanks!