While I had confidence to do anything on a car, there were certain things I left to the pro's. I did a few dozen shift kit/plate jobs in my day, with great results, but considering the time involved and the tools needed for a complete overhaul on a auto trans, i had them done for me.....Mostly by ATI, which was just 7 miles from my house at the time.
I know prices are steep now vs the seventies when I was involved, but I still think getting it done by a solid shop is $$$ ahead in the long run.