Alright, so I've been in a very similar boat to you.
My first ls platform swap in 2015 was an 86' c10, 2001 5.3, ls6 cam, with a built 700r4. I bought all the conversion bracket and cables for the DBC throttle body from I think bowtie overdrives. I've adjusted my share of kickdown and tv cables, and I never got this sh*t to work right even after chatting with them. High line pressures and bizarre shift points. The 700r4 worked flawlessly, good line pressures and shift points in my buddys camaro with a 355.
I eventually grenaded that 700r4 in spectacular fashion when doing a rev limiter burnout, shot the servo cover somewhere never to be found again and dumped an estimated 8 quarts of atf on the road outside my apartment. Roommates helped push it into the garage, and I eventually went with the proper 4l60e and never looked back. The 4l60es never really held up to my driving style, but always performed and you, and your tuner with thank you with shift points and torque management you can adjust right there in the tuning software.
Now to today, finished up my 4.8/4l80e elco this spring. Before that I had a poorly built 355, and a 2004r built by extreme automatics and a nice converter. Sold the 2004r to a friend for less than half what i bought it for, and spent less than half of that buying a nice used low mileage 4l80e. Used lt1swap.com and the stock harness re-pinned in less than an hour for a 4l80e.
My advice, buy whatever 2wd auto came with your harness. If you want to go from lets say a 60e to an 80e, just do your research and make sure it's something you can handle.
Also, putting the dbw pedal in these cars isn't that bad from what i've seen. Did a swap not too long ago on a bmw using that pedal and it works flawlessly and wasn't that bad.