msseeker, I believe that miniskirts are classified as Bigdei Pritzus. I don’t think Rav Wosner drew the line somewhere. He didn’t mean a dress that is questionable according to some, he meant miniskirts etc. And only one reason he cited was wearing it in a Tznius fashion (which you can do by adding a panel).
On the questionable clothing, there is a Teshuva from the Kloisenburg Rebbe ZT”L (who maintained that wigs are an Ervah just like hair) that permits selling Sheitels because there are those who are lenient (I’ll try to get you the M”M ASAP.
I saw an important question raised here about a new phenomenon going on in the Frum community. Women go to male hairdressers to style their wigs. There are issues besides Tznius (such as a MUST to support a fellow Jew, if it isn’t significantly more in price, although the service or quality is somewhat better and so forth) but in a Tznius thread we’ll stay on topic. The Debrecen’er Rav discusses this (sorry for the exact again, you know there’s no web in Beis Midrash) and rules it explicitly Assur. Reb Moshe has a similar case which he says is not accepted and claims that although the man may be doing it for business, it might lead to unwanted situations, willingly or forcibly… He goes on saying that men should forbade their wives from doing so. You might want to differentiate between the situations, whereas in that case (swimming) a woman’s body would be exposed. However, I see it being similar or even worse, this case has direct contact, touching and beautifying a woman.