Better DAMOS are out there but you have to pay for them. Those companies who have them paid for them and are under no obligation to provide them. That said, all the initial XDF work I did was with the freely available pre-production DAMOS.
The GM ECU you speak of, how many tables did that have? Because I don't see anyone sitting down and doing all 25k+ MSD8x, and then doing it
3 MORE TIMES to cover all 4 roms, as the good DAMOS only covers one. And that's being generous and assuming all tables exist in each rom, that the axis sizes are the same, and that the data is close enough to hex match. But it isn't. Much logic was rewritten going from I8A0S to IJE0S, and then again with the jump to [IKM0S and INA0S]. Table sizes increase, tables were dropped, tables were added. Then there's some shared axis whose values exist 5+ times in the calibration area. Which one maps to which table? The only reliable way to trace these kinds of things is in IDA.
As for the Helix changes...I sent a few of what I had from the past to
@Sbrach along with some ram addresses to aid in the tuning. He then dug up the rest of what was needed himself.