This is gonna sound insane but you could have the blueprint built in a partially isolated "testing" area. Once it is fully built (based on a delay or some logic in the blueprint itself) you power down surrounding robo-ports (creating a local logistics network), deconstruct the area of the blueprint, and then measure the change in blueprint materials in the logistic network.
There is probably a MUCH better way to do this but I see no reason why this wouldn't work.
