Have no "exerpience" on this matter, but the "G" force on dovetailed sights mounted on a semi-auto pistol slide is greater than one might suppose; if the instalation is "a little shaky", chances are that before 100 rounds are fired you will be waiting 'till dark to look for the missing Trijicon. If the instalation was done by someone else, I would send it back and politely ask them to do it again -- this time correctly. If I had performed it myself, I would review my work and, if that were faultless, think about other options. Lacking a suitable alternative such as returning the sight , I would consider the judicious use of wicking Locktite. If it will prevent movement of the locking cams of an MG34 machine gun, it will sure as hell hold the rear sight on a P99.
M