Small update - patching the uneven OSB edges took longer than expected... what a PITA. To add insult to injury the OSB from the lumber supplier was the worst - LOWE's was actually all even at factory edges.
Anyway we spent some time getting our reference lines lasered, and measured everything out. You guys are going to think I'm crazy (the CAD) but whatever: the blue lines are measurements off our laser. As mentioned we started by making our ref line perfectly parallel to the Living room wall. Took the perpendicular off of the main run, down the foyer, then re-setup the cross laser into the office. From there measured the distance from our reference/laser lines to all the 'horizontal' walls/features, shown in blue below. In addition the distance between the two horiz laser references. All the measurements within a flooring area (for instance from both sides of the living room to our ref), was within 1/8-3/16" with only one exception: the two narrow walls dividing the TV and Dining spaces, they were off 5/8" of an inch from one another. I'll take it; I feel we got very lucky.
(I removed some of the vertical walls for clarity). In addition since the double measurements within a room were so close I only show one measurement line per space below. This was just to get everything to scale/referenced.
Got actual measurements of flooring and have been playing around with placement, primarily to avoid 'slivers' or 'schnitzels' as Incognito so affectionately called them.
Best I can seem to do leaves me with a 2-1/4" strip down the French Door wall in the Living room. That was a compromise to give me nearly a full plank along the opposite wall, full/half planks in office, 2/3 plank at entry door/TV top wall, ~1/2 plank or greater everywhere else.
(I don't expect you to make out anything useful from below):