Fuel Tank
The fuel tank is not difficult to install. It may be even easier, however, if it is done before installation of the seat belt/shoulder harness and the stringers. The shoulder strap is only slightly in the way and the fuselage stringers make it a little more difficult to drill through the upper tanks gussets. If your like me though and like to follow the order in the manual, you will not have a problem. The only question on installation I have is that it list four bolts, four nuts and only 3 large area washers for the installation. Seems like there should be four. I think I'll add the last washer! Pix below!
Notice in picture #3 the clearance between the elevator bellcrank and the fuel tank. Picture #4 shows the mounting of the fuel tank and the large area washer.