I would agree that Sophy is a bit bumptious, as far as Heyer heroines go !
I have been pondering which Georgette Heyer book to recommend, to give you a better idea of the range of heroines which she portrayed.
I am currently reading "Sylvester", where Phoebe is the most unlikely heroine, but that is very slow until about page 100, though the plot is highly original.
I am thinking that perhaps you might enjoy "The Reluctant Widow" rather better, or possibly "Venetia".
"The Unknown Ajax" is also an excellent read.