Data point:
I have my Albatross bar on a 10cm Tallux stem. I have my Bosco bar on a 12cm Tallux stem.
To me it *feels* like the Bosco comes back towards me a little more than the Albatross bar, even given the 2cm additional extension and the lower height of the actual stem (the Albatross and Bosco hand grips are pretty close in height, which means the Bosco bar's stem is lower, which means its clamp is pushed slightly further forward than even the 2cm greater extension would suggest).
My comparisons are subjective. But they are in the context of identical frames, saddles, and saddle height and saddle setback.
FYI,
Thomas Lynn Skean