It's a good technique. When I specify the dimensions, I just go by the bottoms/tips of the panels. That way a builder can draw a line or use a stationary straight edge and put the panels right up to it.

: I haven't seen this before. I have devised a way to accurately and easily
: align plywood panels when scarfing them together. I like to mark out and
: cut the panels separately to make the most out of a sheet of plywood and
: have found it a bit fiddly when aligning the pieces to join them.So what I
: do is make an Index Mark on both ends of both panels 2" up (or
: whatever measurement is convenient) from the baseline when marking out and
: then I find it quick and easy to align these marks using a laser line, or
: a string line.Please see attached diagram.
: Robert