A hint about the stacked blank idea.........................

Stack twice as many blanks as needed for one wing. Taa Daa...... you wind up with two wings worth of ribs AND....... the taper that winds up sanded into each rib's edge is appreciably lessened.

At first, I thought that I might be wasting balsa to have an extra set of ribs. Turned out that I built wings with every "extra" set I ever produced. Matter of fact, the last couple of times I made up ribs, I stacked enough blanks for 3 wings. All three were the smoothest I ever built. And when I was "dealing out" the three sets from the big finished stack, after I got the three stacks, I numbered them. Then I selected a "best wing set" and a "worst wing set". Turned out that all 3 wings flew like gangbusters, but I'd do it the same way again.

BTW, yes, the stacks get pretty large. But it's still worth doing. You'll discover that finding bolts long enough is a minor effort, and that the threaded rod that works great is not only easy to find, but long enough for about any stack.