Changing parameters in CSG CGAL mesh generator has no effect on resulting mesh

mesh
1

I am using Fenics 2019.1.0 on Ubuntu and would like to use the CGAL modules to build meshes where I can modify the mesh generation parameters. I find that on modifying any of the mesh parameters below, no changes are observed in the resulting mesh. Am I doing something wrong? How can I control the mesh density in certain geometric regions (e.g. re-entrant corners, curves, etc.)?

from dolfin import *
from mshr import *

C1 = Cylinder(dolfin.Point(0,0,-2.5), dolfin.Point(0, 0, 2.5), 1.0, 1.0)
C2 = Cylinder(dolfin.Point(0,0,-2.5), dolfin.Point(0, 0, 2.5), 0.5, 0.5)
B1 = Box(dolfin.Point(0, 0, -2.5), dolfin.Point(1.0, 1.0, 2.5))
Coax = (C1 - C2) * B1
generator = CSGCGALMeshGenerator3D()
generator.parameters["edge_size"] = 0.1
generator.parameters["facet_angle"] = 25.0
generator.parameters["facet_size"] = 4.0
generator.parameters["facet_distance"] = 0.01
generator.parameters["cell_radius_edge_ratio"] = 2.0
generator.parameters["cell_size"] = 0.02
mesh = generator.generate(CSGCGALDomain3D(Coax))

info(mesh)
plot(mesh)
plt.show()