Not sure about the shutter on the Butcher Popular Pressman, I make shutter curtains for other similar British SLR's but ideally a pattern helps. (I supply curtain material to a leading US repair man). I've 3 SLR's sat here waiting for new shutters but a back-log of restorations/repairs.
Most British shutters are rather more sophisticated compared to Graflex cameras, that's an advantage as they need much less shutter cloth and two curtains as opposed to one long continuous curtain with a number of slits.
There's a few variations to the Houghton Butcher focal plane shutters depending on the age of the camera.