I seem to remember a thread a while back about adapting a RRS TA-3-LC leveling head to the larger tripods with a 100mm apex opening such as the Leofoto 404-c. I didn’t feel like searching for the thread so if this has been covered, oh well. I stumbled across a 100mm to 75mm adaptor that looks like it may fit the need. Enjoy.
https://www.amazon.com/LEOFOTO-Adap...ds=leofoto&dpPl=1&dpID=41WXxH41-wL&ref=plSrch
https://www.amazon.com/LEOFOTO-Adap...ds=leofoto&dpPl=1&dpID=41WXxH41-wL&ref=plSrch