(a) According to page 26: what is the HALACHA for women who come to the western wall (the KOTEL) after 30 days. Do they have to tear KERI'AH? surely, it's a public area and not a modest act?
(b) What is the HALACHAH on hol hamo'ed?
(c) do all the pilgrims who didn't see the kotel have to tear KERI'AH twice (once for Jerusalem, once for the KOTEL)?
(a) Women are obligated to tear Keri'ah for the Churban. Some authorities require them to tear their shirt, but others are lenient and permit them to tear any garment they are wearing, such as one beneath their shirt where the tear is not visible. Also, a woman is allowed to close-up the tear right away with a rudimentary stitch (such as with pins), for the sake of modesty. (Both men and women are not required to tear their undershirt, as the Gemara says with regard to the "Apikarsuso," which some Rishonim explain is the undergarment.)
(b) It is a custom among the original residents of Yerushalayim not to tear Keri'ah on Chol ha'Mo'ed (RAV YECHIEL MICHAL TUKACHINSKY zt'l in IR HA'KODESH V'HA'MIKDASH). If one arrived at the Makom ha'Mikdash on Chol ha'Mo'ed, he does not have to tear Keri'ah after Yom Tov. Similarly, if one arrived at the Makom ha'Mikdash on Shabbos, he does not have to tear after Shabbos (ibid. 3:17:4, MINCHAS SHLOMO of RAV SHLOMO ZALMAN AUERBACH zt'l, TESHUVOS V'HANHAGOS of RAV MOSHE STERNBUCH shlit'a).
On Erev Shabbos after midday, the common practice is not to tear Keri'ah since one is already wearing his Shabbos clothing (see Minchas Shlomo, IGROS MOSHE YD III 52:4). Even though the CHAZON ISH challenged this leniency, certainly one does not tear Keri'ah on Erev Shabbos after Plag ha'Minchah if one has already accepted Shabbos upon himself (SIDUR MINCHAS YERUSHALAYIM). (See "Sefer Tel Talpios, Hilchos Keri'ah Al Arei Yehudah v'ha'Mikdash," Oraisa Publishing 5759.)
(c) RAV TIKUCHINSKY (Ir ha'Kodesh v'ha'Mikdash 17:2) says that the practice is not to tear Keri'ah on Arei Yehudah separately. Rather, only two Keri'os are made: one for Yerushalayim, and one for the Mikdash, and before tearing one recites the verses mentioned in the Gemara.
When tearing Keri'ah for Yerushalayim, one tears only when he sees the original city ("the Old City"), such as the city wall around it, or the roofs of the houses inside it (Rav Tukachinsky in SEFER ERETZ YISRAEL). Some, though, are stringent and require one to tear for Yerushalayim only upon seeing the part of Yerushalayim that had Kedushah (which is the present "Ir David" and the area south of the Makom ha'Mikdash).
Some Poskim are lenient and do not require Keri'ah for Yerushalayim at all, since the city is presently under Jewish dominion (IGROS MOSHE OC 1:70:11). RAV SHLOMO ZALMAN AUERBACH zt'l, though, ruled stringently, that one must tear on Yerushalayim even today (Minchas Shlomo 73).
When tearing for the Mikdash, the practice is to tear right when one sees the Kosel, even though he has not yet seen the destroyed and desecrated place upon which the Mikdash stood (upon which has been built a mosque).
The second Keri'ah that one makes must be at least three Etzba'os, or about three inches, away from the Keri'ah that one made for Yerushalayim when he saw the city before the Makom ha'Mikdash. The tear for each must be one Tefach in length.
(Based on information culled from Sefer "Tel Talpiyos")
-Mordecai Kornfeld