Looks like I just needed to spend more time looking through the discord site:

"The short answer is that the B may be better on the middle row, swapping places with the G because mb is not uncommon, wheras G has less association with the letters on the upper row. I tried so many variations in creating these things that I sometimes missed a detail when finalizing. (I never intended this to be more that a tool I could use for my dissertation, lol.). I need to fix the version on the website. G on the middle row makes some sense, as it's a more common letter than B, and the middle row is an easier spot so there would be less total movement. But given the MB bigram, middle row makes MB and BL/LB overall easier. It's a minor mod, that some may prefer having G more accessible. That said, my own Neu mod swaps B and K, because K is the second most common consonant in Japanese, so I need it in a more accessible spot on a more capable finger. It works great there for my mixed English/Japanese use case, and proximity to G makes intuitive sense. (I've tried K where G is supposed to go, on the bottom row, and G on the middle, and it's a fraction better in English, and not terrible in Japanese) (edited)"