Hi Dave,
IME, Pelikan nibs in gold run slightly narrower than Stip nibs in the same nomination, but still fitting within the size, and steel nibs run slightly wider.
The problem is that even within nib sizes from the same manufacturer, there is a variation in actual widths, which also seems to depend on the period of manufacture. I assume the pen manufactuers occasionally rethink thier nibs, resulting in slight differences.
I have a few "older" Stips which defintely write wider lines in M than new ones in M.
OTOH, the new Stips are all writing within the "generally accepted nib-width principles" (GANP

) as in Richard Binder's nib width chart

, as far as they have standard nominations, that is.
Ok, to answer your question more directly: they run about the same in width

.
BTW, if you want to check some of the Stip's nibwidths compared to other pens, just check my ink reviews; I think I managed to compare 22 different nibs in one of them

.
Note that nib widths may vary with the ink used as well: wet ink, wider line; dry ink, narrower line.
HTH, warm regards, Wim