First question to ask and answer: How accurate must the dimensions be? What is the accuracy of each considered method? Don't blindly accept a number merely because "it is written".....this isn't the Bible, faith doesn't cut it at precision rifle shooting distances..., or displayed on a screen..... Hand grenade accuracy merely adds to the variability in your shooting process. It's like using the Muzzle Velocity as listed on the ammo box.....yeah, that might be the number, but probability says NOT, for your barrel, location. GPS has a tolerance. Even surveyors have a +/-.....hence "400 acres +/-". Example, when confirming scope precision/tracking/repeatability, don't step it off, don't range it, MEASURE with a tape from target to point of turret....not barrel muzzle, not scope objective lens. Variations in the distances may be good enough for your needs, but don't move ahead without asking/answering that point. CONSISTENCY is KING; ACCURACY is his QUEEN. Just a really, really old engineer kinda guy's life observations. YMMV, but I doubt it.