[Gmsh] Unstructured hexahedral meshes

[César A. Vecchio Toloy]

Hello to everybody.
I've been using Gmsh for a while to mesh with hexaedra around an airfoil, using transfinite, extrude and recombine algorithms. I never had a problem, but given the way in which the space discretization is made, I would like to know if I there is some way of creating unstructured hex meshes by means of the same algorithms, in order to lower a bit the element quantity (my PC is not exactly a great number cruncher).
Choosing plainly a tet algorithm and then setting "all hexas" in the GUI is not a choice. I tried setting different nodal discretization on two opposing sides of a same transfinite surface but Gmsh says that cannot be done, that dimensions should match. So on that surface the transfinite algorithm is not applied and that part gets an unstructured tet mesh.
I only need the refinement around the airfoil and its wake, the rest of the flow is little pertubed. I was thinking of superimposing a new identical line with different discretization over an existing one and in that way I would get what I want, but the volumes are not going to be connected. Would that be an issue? Are there alternative solutions?
Thank you in advance.

César