No workflow as such needed. The plotted files from PCBnew are directly compatible with cirqwizard, after you have changed the file names (select the option to use protel file name extensions):
test-F.Cu.gtl to test.cmp
test-B.Cu.gbl to test.sol
test-F.Paste.gtp to test.crc
test.drl to test.drd
test-Edge.Cuts.gm1 to test.ncl
If I want a custom board outline, I draw it in Fusion360, export as dxf then import the dxf into the edge cuts layer in kicad.
If you go this route, you will have to turn off the board outline in cirqwizard, and make sure you manually insert nibbles onto the board outline.