Just remember to not but join them, but cut each end on a 45 and fit them together. It helps if you can arange to have a former mid way through this seam.

Also remember to true up the edge so you have a straight edge to work with. It is real easy to get a step, or a bend at the joint line. One trick to remember, If you lay the two pieces one on top of the other, and make sure the edges line up, then make the 45 cut through both pieces at the same time, it doesn't mater if you are cutting exactly 45, or 42, or 49 degrees, When you flip the top piece over and but the two angles together it gives you a straight sheet

Ive built several planes using sheeting joined like this for both fuselage sides and wing sheeting. I've yet to have one of these splices flail even in a crash that destroyed the plane.

Don