Now here's a thread I can get into.
I found that backing off a wee bit on the protein content of kibble firmed up the stools on my two mixed Mau kittens and as grown adults. Out of these four varieties, Royal Canin, Wellness, Orijen and PureVita, the last two were the most successful but each cat is different. I used to provide kibble as a snack only to an otherwise wet food diet and have gone fully wet since bringing Isis home.
I agree with your sentiment that backing off on protein content, for example in 5% increments of the protein to fat ratio by dropping 5% protein for 5% more fat content and see how that goes is a worth a try. If you look at the ingredients of Adult vs Kitten formula, you'll find the kitten variety is slightly higher in fat to aid in digestion and build up those energy stores. The number one issue with kibble is moisture followed by being a processed food.
I've started an experiment with soft boiled eggs yesterday. Coincidentally, today was the first ever food rejection from Ra which was half a soft boiled egg with yolk and white crumbled with wet food. The yolk by itself last night was not an issue, but mixed with white was too much for him to be appetizing. The other two readily devoured it with the rest of the food. In fact, Isis knew the smell of eggs as part of her breakfast when she was with momma before I brought her home.

She attacked a small piece of shell that hit the floor and crunched it down begging instantly for more.
I also have the same, oh you're going, I'll go with you in the master bath. I think it's funny, adorable, and silly all at once. I would not be concerned there.
Where did you get the measurements and what's the technique for this? Getting total length is relatively easy by having them stretch out to their full capacity but the length (head included or not, from base of neck or shoulders?) and height (from shoulders and standing on all four or sitting) is supposed to be done how exactly?
John and I have talked about cars too. I'm a Jaguar XJR and Toyota Supra Turbo household, looking to add a Jaguar Series 1 XJ6 or XJ12 to the garage in the coming months as a luxurious, understated cruiser. Another Jag is more readily accepted by family and friends than a 4th cat (another SV) I'll tell you that much!