I feed off a lot of adults to my parsonii(who's still under 300g I believe) even discoid males and orangehead females. You can see them chewing up the ootheca from the female roaches, which probably contains a lot of extra nutrients that wouldn't be found in the males. I agree on the nymphs, my guy loves the adult Male dubia, but if you look at them vs a large nymph even, the nymph has a softer shell, but is more meaty. The adult females on the other hand are usually very plump. One thing to consider with adults vs nymphs, while the nymphs might have a higher meat to shell ratio, the adults/older nymphs should have absorbed more nutrients over time and have a higher vitamin content assuming they were raised on good food. Although with roaches this could pose a problem because they have the tendency to convert extra protein into uric acid and store it. So adults could store a lot up if given too much protein. It's important to limit protein for roaches in order to avoid gout.