If you can't get a socket on it but you can get a wrench on it, I assume your concern is not being able to torque it properly? If that is correct, you should be able to do it by feel. Put your wrench on one of the others, feel how tight it is and approximately match that. Pretty scientific, I know.
Another option would be to get you some crows foot wrenches and put them at the end of the torque wrench. Problem solved. These will come in handy other places in the build. Wish I had some!
EAA Tech Counselor
RV-9A #92103 - N803DK
G3X, Superior XO-320, Dual Pmags, Catto 3B
1974 Bellanca Super Viking - N16AW - Flying
RV-8 #83565 - N184DK - building
1968 Mooney M20C - N6801N - Sold
1956 C-182 - N744W - Sold