ELW....looking forward to your results with the smaller pan..and thanks for experimenting.
as you rightly mentioned, in larger diameter pans the heat is spread over a bigger area, whereas on smaller pans the heat is more concentrated.
makes sense when you think about it.
larger pans with medium burner= most heat is centralised in the pan with the outside areas cooler.
smaller pans with medium burner=heat is probably equal throughout entire pan.
I've noticed this while cooking with my larger pan. When adding base sauce I have to add it centrally to get the instant "sccchhhhhhewwwwww"

When using my smaller pan, it doesn't matter where I add the base to get the instant "sccchhhhewwwww"