If you build per the plans (I did) the two foot wells and the small floor section riveted together are easily installed/removed but do require some flexing and are not just a drop-in. If they were riveted to the two large floor pieces farther aft they'd be impossible to remove (I think). I riveted the two main floor pieces (mid and aft cabin) down too early - before drilling for the flap stop/fairing! Rats. Much to my surprise it took less than 10 minutes to drill out the pop rivets and remove the floors. After doing drilling and install of the flap stops/fairings it took less than 10 minutes to put the floors back in and rivet them with an inexpensive HF pneumatic pop riveter. I believe doing the nut plate screw route would: a) take a lot of time, material and work; b) weigh more; c) take longer to remove and install than the pop rivets. Hopefully you'll get other opinions which will help you decide. In my case I found little under the floors I couldn't secure adequate access to from forward and aft openings.Good luck!