I take the same size (9e) on all lasts. I would say that for my feet, tg73 is the narrowest and deco is a bit more comfortable from the beginning.Do folks who have square deco shoes take your same size and width as the normal lasts or do you go up one size in width? Came across some older posts of people going with F width for their square decos.
I guess ot depends on your foot shape.
for reference my size is usually 8,5 with John Lobb, Saint Crispins etc.