Nah I had just used a sanding block on that, and only put 1 board down so that I could start out into the hallway. I didn't finish that doorway yet.

Alright Dave! That turned board looks great, just as it should. Don't forget to blind nail into the groove side of your turned header board AFTER you finished the field installation and remove your backer boards. It looks like the 6-8-10 deal did work out. This is the way we have been figuring 90 degree angles for over 2000 yrs. Of course, 90 degree lasers are very nice to have and are worth it for a regular user. But since you're already getting grief from the wife about buying tools, no reason to add fuel to the fire!
The Pythagorean Theorom works great if you take the time to measure carefully.
http://mathematica.ludibunda.ch/pythagoras.html