Thanks Chas and JohnDThompson--- that's exactly what I was struggling with: the travel stop tab on the Shimano Crane derailleur (which Chas shows so well in his post) won't fit over the Huret dropout on my Raleigh Competition without modification. The modification I think I need is to file a notch or a slot in the dropout, just like the modified Schwinn dropout JohnDThompson shows.
Thank you all! I think I can just use a flat file to notch the dropout, and a bit of paint afterward.... I've already run the 10mm x 1.0 mm tap through the threads.
Cheers to you all.
N