Congrats on the Beyond Centauri sale. I think you'll like working with the SDP crew.
Sam's Dot Publishing puts out a good collection of magazines. Something similar happened to me. I sent a fantasy story to KidVisions (the fantasy side for kids). Although it was too long according to the guidelines, I suggested it could be a serial. No on KidVisions, but the editor took it for a standalone. It'll be coming out as a chapbook in January and then he took two more in the same fantasy world for April and July.