What a lovely poem and essay. I echo your sentiments about emptiness (and also fullness). Have you heard the chant Om purnam Adah. It's sort of a koan in itself, about fullness. Just for giggles, here's a link to a poem I wrote about it: https://medium.com/scribe/perfection-83fb445e0066?sk=a63f766dd40fbdf88651ed74c722582a