Maybe you should practice on n66u firmware for Merlin firmware. Once you gain confidence that you can flash Merlin firmware on rt-n66u and then put back stock firmware and reset to defaults and then manually configure from scratch.......because if you don't have confidence to do that with your main router it's probably a bad idea since your wife needs for work. Otherwise you might get lumps of coal in your Xmas stocking.
Most geeks on this forum can jump from firmware to firmware in less than 10 minutes and put things back to where they were from scratch. And not disrupt their household Internet for more than 10 minutes. Also, most geeks on this forum are confident because they know they can use firmware recovery tool if something goes awry.... So they're not even worried in the least.