I started with a coot and I wasn't happy with the strength of the tail and it was suggest to use tailboards just like cork. The rig will be used in ND where in and out of the truck, in samll boat or a sled dragged will commonly occur. So I wanted to error on as strong as possible, I tend to treat my decoys like plastics, I will see how balsa holds up though. This balsa came pre-glue to 8"w, even though I ordered same density I found some peices in the block quite a bit different and was concened about a number of the peices strength couple of them in the center. I won't order it again this way, I will glue it up myself then I may try to carve in the tail.
Regarding the gap, my cutout is a simple teardrop and the final shape will be at the tailboard, so there won't be any gap once its carved. My patterns aren't always sqaure on the block, and just use a psuedo jig to cut them in.
thanks for the thoughts
Bill