The alignment jig is a very helpful tool. I found that when I installed a wing, I would tinker with it, trying to get it just right, and I would be ready to set the wing and I would bump it! Go through the process all over again trying to get it perfect. So this jig allowed me to use my square, measure and pin the wing, holding it in the proper location. I could double check it and then add a drop of CA and recheck. It's difficult to flip your assembly over and add a drop on the bottom without the wing moving so this really helped out a lot. I actually wish I had this years ago, I might be a better flyer today?
The other tool Walter offers is the rib alignment tools. He has a set of rib alignment jigs made from ply wood that you slide over the rib to get the rib perpendicular to the building surface. Walter's kits most or all that I have seen have on the rib a building tab. This tab gives you the proper level to build the wing on a flat surface (glass or sheetrock) then use the alignment tool and you get a perfect wing. If you don't have this rib alignment set call Walter, it is a must have. It's available in 3 different thicknesses as the set.