I can also only answer to question 1. I used a smartphone app called LoseIt that lets you make your own recipes and calculates the calories and other nutritional facts based on the ingredients you list and their amounts. You can easily change the number of servings and it will update the nutritional information for you. All in all, it is a bit of work but it is accurate enough.
For me personally, as already mentioned, I start form a recipe and them make changes and tweaks. Basically, my guideline is no added or minimal added salt, fat and sugar, so I start from there and remove/replace any ingredient that does not fit that very basic guideline.
Hope this helps and I hope you find the answer to your second question!