I need some help finding sources for great people who left out the second half of bentching (i.e. everything from the harachamans and on, after the four blessings). Most people seem to have the custom to say that part, and that custom must have been around for a long time because the Tur (Orach Chayim 189) defends this practice, but I have heard that Rav Chaim Soloveitchik and the Vilna Gaon did not say that part. However, I have never seen sources discussing the practice of either of these two rabbis and was wondering if anyone could provide such sources, or sources discussing the practice of any other great people who did not say the second half of bentching.
According to סידור הגר"א בנגלה ובנסתר the Vilna Gaon only omitted those verses on Shabbath.
In the 1971 edition, section one, page קנט includes them.
In section three, נוסח התפילות והברכות לדעת הגר"א, note 90, it says:
בברהמ"ז לא היה הגר"א אומר בשבת רק עד הרחמן הוא יפרנסנו בכבוד ולא עד בכלל ולא יותר.
On that note, there is a footnote 116, which says this is according to eyewitness accounts of his students.