I used the standard access hole sizes. A large set of forceps (my big ones were 12" I think) will help with working back there. I was able to get all of the nuts on without larger access holes. I don't remember if I had to do it back there, but I often create a small loop of masking tape to hold a nut to a finger when I can't get two fingers into a small spot to start a nut. I remember having to do this many times on the 6 build. You can also tape a nut into a box wrench to get it started.
RV-6A / IO-320, Flying as of 8/2015
RV-10 in progress
Last edited by lr172 : 06-01-2018 at 10:41 PM.