I’m glad it worked for you!
“why was the local/absolute size multiplier was necessary?”
I set that up on a hunch. My 2D box was initially offset and too large. When I changed the viewport size, the size of the box changed with it. Based on this info I knew that the unit size of the 2D space was missing a multiplier to shrink it to match my viewport size. The division of local widget geometry size by global widget geometry size is finding the percentage of the screen not taken up by editor window widgets (I assume). This would not be necessary if my widget geometry took up the full screen, which it probably does in Standalone Window mode.