So, with efile being (anecdotally) awesome right now and a few other factors going my way, I am thinking about taking a shot at an efile SBR stamp. I still need to work out a few details (caliber, barrel, traditional stock or PDW), so I can't just ask "hey what would this configuration be?"

Instead, I'm curious what method you folks use to get the OAL without actually assembling an illegal SBR to take a measurement. I'm thinking the easiest way would be to measure from the muzzle (sans device) to the pivot pin on the upper, then the pivot pin to the butt of the (extended?) stock and add them together.

Yes, I likely am overthinking this.