Which bin to start with

[RS Morgan]

Should I be starting off with ACSU bin for 700r4 trans? or ACSR bin for turbo 350 trans? I have the turbo 350 in my 87 blazer. It came originally with a 700r4 so common sense tells me to go start with the ACSR bin. I downloaded both and compared them and noticed the timing tables are only slightly different, why is that so? Gear ratio is 4.56 with 35 inch tires with vortec heads if that would matter in which choice of bin file to start off with.