I just remembered that we typically get some rain in February and March so I think I'll plant some in the ground and top off with mulch and then tarp or plastic over them.

Digging of dahlias for the winter is done in cold climates to protect them from freezing. Where you are there is surely no need - and they would be better off getting back into the ground.

Unless the planting site is expected to become too wet during winter rains. In which case another planting site should be found anyway.

Thank you Embothrium! I will start planting them in the ground in the next couple of weeks. After I divide the tubers, do I need to let them dry before planting?

A bit late to the conversation... no need to dry the tubers if you're just going to replant them. Best to keep them plump and ready for root growth.

I'm a big advocate of trying multiple methods simultaneously, as the learning curve is a bummer if you have nothing left to experiment with after a failed attempt.