I found a tape measure easiest to measure against room boundaries while making REW measurements at 4" intervals. When I was done with REW, I used a laser against a paper target at the listening position to mirror the speakers' distance to the listening position, and toe-in.
Speaker Positioning
I know from speaker position is critical in achieving the best results from a given system. Is there a dynamic way to measure placement of each speaker to make certain they are the exact same distances from back/side wall, cabinets, seating, etc. beyond a measuring tape and listening to the results? Seems to me if minor differences pay large returns, you could be tinkering with this a long time. Thanks for the indulgence.