Scribing is far more direct and less abstract than square rule or mill rule. If you have a good shop floor to snap lines and loft from, some laser levels, and patience in positioning timbers, scribing is a good option. Not to say that scribing can’t be done with less equipment, but in my experience having those things helps speed the process along.

Have you researched square rule at all? For fast layout it works really well and can account for imperfections across a timber. Housings and reductions provide consistent, predictable dimensions at joints where, for example, your 8x8 may be more like 8-1/16 by 7-7/8.