https://www.joshsfrogs.com/digital-pocket-scale.html
This is the scale I use. It's fine but small, it does have a tare button so you can put a bowl or something on it.
You can never have an enclosure that's too big, you can, however, have an enclosure that's too open. Make sure you have multiple hiding places, whether its fake plants, half logs, caves, cork bark or flats, or just a rock they could hide behind. That makes them feel safer and prevents fights...
Silkworms are very high in nutrition and protein, but they are a bit harder to find and more expensive. I get mine off of rainbow mealworms occasionally, it's 8.99 for 15 of them. Another good choice is hornworms, they are pretty nutritious but low in protein, 8 dollars for 12 or 25 ct on...