Chances are, the Joann's clerks were rude because the didn't know. Many are not expert seamstresses... or even OK seamstresses.
Or the fabric fumes got to them.
Just "pity their ignorance and despise them" (Charles Dickens. Not an expert seamstress either.)
SO -- any thoughts on the Simplicity vs. the McCalls? IMHO, the SImplicity has a better skirt -- more A line and less gather-y. And I like the long, band-less option. I think the bottom band may be 1 contrast fabric too much for me... another honking big horizontal. OTOH, I do have terrific legs.
What to emphasize: Nice tits or terrific legs?
Bette Midler had a song "Pretty Legs and Great Big Knockers" Could be a ring tone....
Underneath the needles you've used as markers, there are stitches. Put a piece of contrasting yarn to mark those lines, and remove the needles. Then stick one needle through each knit loop where the yarn is. What you'll end up with will look like cast on stitches on the needle. (Try a smaller needle to stick through the loops/pick up if it's too hard to use the bigger needle.) Remove the yarn marker. Then knit the picked up loops with both needles untill you're done with the flap.
Most picking up stitches is more intuitive, because they're on the edge. So you're doing it the hard way first.