I've referred to interesting comments regarding Wessely's commentary to Leviticus which are found in Moses Mendelssohn (Hamburger)'s book פני תבל: מוסר השכל (Amsterdam, 1872), but I finally have a chance to post them directly.
Later he discusses Wessely's writings in general (below) and be sure to read the last line to see who, as of that writing -- he died in 1861 -- was in possession of Wessely's manuscripts.
R. Samson Rafael Hirsch was his nephew. See the following from pg. 108:
