LS3 with t42 and 4L80e

As the title says, mating an actual LS3 (not L99) with a 4L80e behind it. I know it's been done before but how involved was the tune? Does the e38 TMC not care what TCM is behind it, just that there is one there? I'm trying to decide the best base file to start with. Maybe an L99/6L80e from a camaro, turn off AFM and VVT? But then what about the 4L80e trans file. I also have a file for a LY6 6.0 with t42 and 4L80e from a late model express van. Maybe it would be better to start out with all the framework for the t42 to be correct and tune the 6.0 file for the 6.2 LS3? Any guidance is appreciated.

Also apparently there are 5th gen camaros running around from the factory that were LS3 with 6L80e but I can't find a tune for one. My gut tells me that would be the best place to start if I could find a file.

Maybe I'm overthinking it...

Any help is appreciated.

I should add, I was hoping to accomplish this with a 2012 ec8 #12647991. Perhaps an older e38 would be better suited.