1)
In VW2010: I've now tried out using a single 510mm leaf wall (black for existing building) then in window settings using a negative jamb width (-63.5mm for 1/4 brick)and a 95mm plan wall offset calculated to leave me a jamb outside the window of 125mm (window as casement with sash width 80mm, depth 70mm). This places the window in the wall and the window frame embedded in the wall. I then add interior trim with width -63.5mm and thickness calculated to be the remainder of the wall thickness (=wall thickness - 125mm for the outer jamb - window frame thickness, here 70mm)
Show wall lines is switched on.
The 2d plan representation is ok, there are 2 extra lines for the interior trim that I could do without but I can use the window and vary the width or the casements or placement for the wall depth. For other walls I need new settings for offset and interior trim thickness.
2)
The other option is to use the exterior components method. I have to then define each external wall type with an external 63.5mm component, all in black and then set the offset again as before and then set the jamb width to be 63.5mm or greater. This works quite well and is good in both 2d and 3d.
Method 1) is good becaue I don't need to worry about my wall definitions but then I need to fiddle with the window settings a lot. And there are extra lines in 2d and it doesn't work on the internal side in 3d as the trim is solid.
Method 2) is good if I set up wall definitions and just generally have an external leaf of 63.5mm in all external walls and set up the window frame measurements for the first window. All I need to calculate is the offset. You can adjust the offset for multiple windows but the 63.5mm reveals do not automatically follow the window frames and have to be adjusted individually which is a pity.
What we also really need are the box-type double casement windows prevalent here. Method 2) is best as I can copy and drag the windows to make the inner window, at least in 1:50 or smaller it looks fine.
Fergus