Maybe if you shared what part you disagree with and why assumptions wouldn't be made.
I do not believe the front foot has to be fully on the ground in order to be optimal. It can be, but it doesn't need to be. Launch can occur at toe touch, but it can also occur prior to toe touch or after toe touch depending on the hitters timing on that specific pitch. But if I had to make a choice, I would rather be early than late. My version of FYB includes >50% of weight on the rear side. I do not think 50/50 is ideal. Once a hitter reaches 50/50, his adjustabillity is already compromised.