If you add the supplements individiually, don't you just throw them in the grinder and mix with the proteins/eggs? If so, then it doesn't sound too time consuming.
Um, rather than "throw them in the grinder", you need to carefully measure portions and use a scale for weighing the meat, as well as measuring spoons, cups, etc. (much like baking) and follow the recipe strictly as directed from the website(s). You may also need to debone some meat to prevent excess calcium intake, which can throw off the phosphorus/calcium ratio, especially rabbit. Dr. Pierson removes 25% of chicken bones as well, and explains why. Several fish oil soft gels need to be pierced with a sharp needle, then squeezed out of the covered coating. Further, she talks about adding liver to her chicken recipe, depending on the type of chicken you buy. She emphasizes that this is very important for a healthy, complete and balanced diet for the cat. So, all that being said, I think this can be somewhat more time consuming process, especially in the beginning, with lots of measuring, portions, deboning, etc. for a novice person who rarely cooks or bakes. But don't let this overwhelm you, Dr. Pierson admits she is not skilled in the kitchen at all, yet she has been able to make her food continuously. Another thought to consider: you'll definitely need exta space in the kitchen and a reasonable space in the freezer to make these as often as you need.
Do you know if the Grinded style is similar to Pate style in the wet foods? The reason I ask is because Mew doesn't really like Pate.
To my knowledge, there are different grinder plates that you may purchase if your cat doesn't like the soft, pate-like texture. Maybe the grinder comes with a few plates already included, so you may want to read up or call the company before ordering. However, know that some harder bones such as rabbit or larger poultry such as turkey would also be in larger chunks unless you debone them first. The good thing, though, is that you'll have full control of how the texture turns out. Chunkier meat seems to be favored by my two felines as well, but I don't know if that necessarily means they won't need a future dental cleaning, either. Perhaps someone who has been feeding raw for much longer can give you their opinion and experiences. FYI, I feed my two kitties commercial raw and occasionally the prey model raw to encourage good, dental health.