THE FIRST thing you must do is sand off the top of the instrument level so that the back fits seamlessly. I did that on the BIG BASS using this large sanding disk. Worked great to level the gluing surface.
And then commenced the crazy and difficult job of glueing the top on. I used about every clamping mechanism at my disposal to not only clamp the lid down tight, but also to hold the sides in to their proper position. After more than a few panics I got it done. The back is on and is straight and looks fine. I will show you tomorrow, now I think I will hit the hay