You can surely run this woofer with just a single coil. Nice and simple. Of course, summing is as much determined by what you have above it, so you'll have to take that into account. The easiest setup is first-order, but like everything else, it works well on some things, not so well on others.

I'm using the WTPro/ST system to re-evaluate all my crossovers. The Smith and Larson system imports my existing Spice models so it's an easy progression. What I've found so far is the existing crossovers work great but I'm sometimes able to move component values up or down 10% or so and get a smidge better response curve. Nice to have that kind of visibility and resolution.