I have a Volume Rasterize Attribute node connecting in to a Pyro Solver node.

The Rasterize Attribute node's Voxel Size is set to 0.1.

Should I match this value for the Voxel Size parameter in the Pyro Solver node, or at least not make the resoluition of the Pyro Solver's parameter greater (i.e. a lower Voxel Size)?

source volume will be sampled at the solver's resolution during sourcing so your source can be the same or lower resolution, (since matching pyro may not always be necessary if such resolution is not needed for the source detail)
I'd avoid higher than solver's resolution

Thank you again Thomas. That makes sense.