One more thing. Based on an idea I read on a mechanical keyboard forum @algernon posts on, I’ve added some tiny squares of grip tape as additional positional indicators on one of each set of thumb keys:
I love the thumb arcs far better than the thumb clusters on the Advantage and the ErgoDox, as they give you an additional typeable key on each thumb and the layout is far easier on the hands. But, I do find myself hitting the wrong thumb key often enough (mainly the adjacent two on each side which both don’t have a homing indicator) that I think this tiny mod will prove beneficial.