How do the Shawplan window frames work on a Lima mk2b/c coach?

[murphaph]

I understand how the window frames work in say a mk3 with Lazerglaze as glazing fitted but how do the mk2b/c window etches work? I take it you file out the pressure vent glazing bars completely, leaving a rectangle, slightly smaller than the etch. The etch is then presumably glued around this opening but how do you glaze these? 

I'm not going to do it, I'm going to use the SE Finecast stuff which is good enough for my rake of Limas but I'd like to know how the Shawplan stuff is supposed to work for these coaches. I have found a few pics on RMweb of stuff in progress but nothing complete.