I did it to mine and it was not easy.
lathe the head down and use a dremel to shape the squish band.
it would be better to lathe the squish band but there aren't any true professionals down here who could do it.
it took me a long time but it came out really good.
the band should match the curvature of the piston and have about .8mm clearance from it.
in the end though I found no real advantage to the head with squish band. Jennings said that they aren't necessary for RPM less than 9000.
their purpose is mostly to lessen heat transfer to the piston by centralizing the heat at TDC away from the edges of the piston.