I use a similar mix to the link posted, minus the dog food. I feed 18% protein lab blocks to all my rats. I also feed this dry mix to moms / pups, but it could be feed to others as well:
Whole wheat dry pasta or veggie pasta
old fashioned oats
black oil sunflower seeds
freeze-dried meal worms (usually sold to feed pond fish)
rat and mouse natural carnival diet by hm brown ("natural" has no pellets in it, which they don't eat anyway)

I also feed moms / babies a daily helping of veggies and boiled egg including kale, carrots, cucumber or zucchini, sometimes other greens as well. My adults get this 2-3 times a week as a treat, the same with the seed mix above.

I also sometimes give them soy milk, but some do not take to it. I may try soaking the lab blocks in it and see what they think.