PM, I have posted on other tznius threads that Rav Falk’s sefer is incredibly machmir on things which have no basis in halacha. Like the color and thickness of socks, which are purely optional to begin with, according to Reb Moshe and Mishna Berura. Also, denim skirts are purely a matter of taste and not halacha. The amount and length of jewelry is another example. He regulates that, but then concedes that for sephardim who normally wear huge amounts and large size jewelry it is ok. What that means is that jewelry, too, is also a matter of taste. I find it hard to take seriously a sefer which basically is based on one person’s opinion of how women should dress, rather than on concrete halacha. Yes, if you want a guidebook on the “frum” or “yeshivishe” style, this is a good manual. (My daughter was once given a camp list which had some rules for the pockets or zippers of skirts which had to either be only in the front or only in the back, I can’t even remember which, but obvioulsy nothing to do with halacha.)
However, if you want to dress your own way, and really want to know what the halacha is, this book has really little information that will be of use. It is a style manual, but not a halachic reference. Halichos Bas Yisroel seems to be a much more unbiased and honest guide to what the halacha requires.