727 transmissions are so complex

I have been studying the books from Munroe and Hand. The information is so overwhelming that I hesitate to begin an overhaul or rebuild. Can you give me a great reason why I should do this myself instead of getting a TCI trans and call it good?

I am building 500+hp 512 ci stroker for my 73 scamp. I was a machinist for 12 years in my past life so i can do it. But why would I want to?

The options are to spend $600 for the kits to rebuild and replace the valve body for strip use.
Or to buy the TCI trans to do it for me. What does your wisdom say??
I read the books 10 years ago and have done at least 40 Transmissions since then the first transmission that I did went in an outlaw Hemi super stocker with 900 horsepower it had already been done so I just checked clearances and replaced frictions but it never blew up nor any of my other transmissions if you'd like to contact me feel free