Tritapatate I have experienced this backlash on every mount I have owned and what I did on each of them is buy or make nylon washers for placing behind the knobs between the housing and steel washer. Nylon can be compressed and therefore I can tighten the knobs fairly tight but it still allows movement and also me to do PA, and I never need to loosen or tighten them ever as they allow movement but remain tight enough not to move after or need any more tightening pressure and they keep the head in position all night long.
