An ideal salad would be a mix of various items that balances out to a Ca
ratio of 2:1. Starting with greens you can add other veggies and maybe a little fruit, since those things usually are lower ratios. Things like cucumber and some lettuces are good for moisture but shouldn't be fed in quantities because they can result in diareah. Some things are high in calcium bunding oxalates (like carrot, spinach and chard) but good greens usually balance out when reasonable amount is used. I'm working on a calculator for illustrating this, I can PM you a link to it of your interested.
I like to change things up so I'll get the freshest greens (collards, arugula/rocket, turnip, mustard, kale etc) and then one or two other veggies. I rotate my greens to hedge my bets as far as calcium or anti-nutrient content, and rotate veggies to try and get things in season or different from last time.
It's important to avoid feeding one thing (or a limited selection) of things day in and day out. Even the good "staple" greens have cons to them that you wouldn't want them to be a single primary food item. Over time this can lead to nutritional deficiencies or accumulation of anti-nutrients. A lot of nutritional problems can be avoided with adequate variety. Even with a good vitamin/mineral supplement whole foods with a wide range of nutrients is more likely to be healthful.
If things are on sale or pepper is eating lots of salad I'll include more things, if he's eating less I focus on good greens or high calcium veggies like squash. Very few things are out and out bad to feed, and some infrequent items still have pros them. I include a little spinach on occasion to an otherwise calcium rich salad, for example. It is high in oxalates so has low available calcium but is a good source of iron and contains iodine. Carrots are high in oxalates but a little goes a long way if you shred it. Colorful things like peppers or squash are often attractive, colorful fruits are often rich in vitamins and anti-oxidants. Winter Squash keeps amazingly and my roaches love it too.
In the summer I grow a little garden with things he can graze on. Thinks like pea shoots, nasturtiums and clover have been good and there are edible flowers you can offer as garnishes or treats. He also likes apples a lot, so I use those as a treat.
Variety in insects is good too, different bugs are high/low in different nutrients. Roaches and crickets offer differnt nutrient profiles as well as some crunch. The crunchy shell of some insects might also be good for dental health as opposed to strictly soft bodied worms. Some insects are easier to gutload, or juicier, or offer more fat. Depending on how old they are larvae can have widely different levels of fat, and I wouldn't be surprised is soldier fly larvae vary in calcium as well with age.
