There are several techniques for baffles. A "box" baffle is often accomplished with strips of netting that form square type tubes in the inside of the quilt. Mega-cold temps can be dealt with this way. You can cram a whole lot of down in one of those things. The offset baffle is somewhat as you have drawn it. The math can get rather tricky in figuring out how much netting to use and how wide the baffles should be. The construction is also a bit tricky but not difficult once you get the hang of it. Essentially you are alternating sewing the lines on the top and bottom of the quilt as you build it. it is edge/bottom/top/bottom/top/bottom/.../edge and the edges are bound off. Three season quilts (the three coldest seasons) will often use this technique. The sewn through is the easiest to construct but also the least warm. It is recommended for warm weather quilts only. YMMV. None of this is carved in stone.