For 1/2 square, I glue two 1/2 triangular pieces together, and attach them to something straight while the glue dries.

Ammonia works by softening the lignin and subrin in wood. There is little or no lignin or subrin in balsa. I use water with a little simple green in it. I think it is a matter of removing a little oil or wax, or whatever, and allowing the water to wet the wood. I'll try water with a little vinegir in it next time.