I'm sure that a good builder could do it, but think of the "average" builder. Keep in mind that things like the alignment of the ribs depends on the jig - a novice builder will be left to his own devices as to how to align them properly as they have no tabs like you might find in a kit.

Again, not a huge task for an experienced builder, but a challange for anything less.

Then of course, they would have to go through all of the additional work and expense of personel involved with plans and a manual! [:@]