Hope Ray doesn't mind me using a bit of bandwidth, hopefully a decent idea.
There has long been confusion about the shape of the CFM cowl, caused by some thinking that it is not round when viewed from the front, this is the Classic
or the side
Clearly there is no flat bit on the bottom on the inside of the cowl, at around the 4 and 8 o'clock it changes slightly, but never goes as flat as some model makers would have you believe, although the lip itself get quit a bit thinner at the bottom of the cowl and there is a flat on the underneath, another thing is that the Fan is bigger in diameter than the opening to the cowl, and drops down quite significantly from the leading edge of the cowl on the bottom, more so than it goes up at the top.
As an aside the dent on the radome was a bird strike coming in to land at Townsville (TSV/YBTL), and as this was an ex Ansett aircraft, and they had no spare white radomes, only red ones put a replacement red one on, later paid the Red Nose day fee after everyone thought that was what it was about.
on the NG's it is quite rounded almost a perfect circle, but the outside changes to quite thinner at the bottom
you can see how the fan is much bigger than the cowl opening in that 2nd shot
and from the side
and the shape of the attachment pylon on the top
Other that the immediate inside of the lip, not sure that much of this is that important in 1/144th or 200th scale, but making the lip rounder is very important for a visual impression.
