I final installed the fuel tanks way back when the wings were still hanging on the jig. Did the final torque of the z attach brackets at that time too. I haven't pulled the tanks off since.
Just installed the wings this past weekend and the fuel tanks remained installed. Not sure why they would need to be removed in order to install the wing attached bolts? So, my answer would be do the final install of your fuel tanks now.
Taylor, AZ (KTYL); Builder #74649
RV7 N789YZ; XIO-360-M1B built by JB Aircraft Engines
67 Cherokee 180C - Flying
My flight bag is made by Dewalt!