This is a hobby because there is no one correct answer - the only thing you’re going to get agreement on is that MDF is still too expensive
That said, build a test box for one of your 10’s and a woofer, and put together a simple 3-way with your Heil so you can do some listening and see if there’s anything that is satisfying to you in that set. If the Heil gives you goose bumps, chase a solution that uses it. If not, try a horn. Have fun and experiment.