As long time user of RTV I take all old gasket off just use RTV.
Clean surfaces of oil and dry take RTV on end finger thinly apply to one surfaces thin as onion skin. Wipe any mash out off try to not have but very little mash out. The only time I use RTV with gasket when gasket used as shim. RTV is more permanent than gasket gaskets shrink over time.
Clean surfaces of oil and dry take RTV on end finger thinly apply to one surfaces thin as onion skin. Wipe any mash out off try to not have but very little mash out. The only time I use RTV with gasket when gasket used as shim. RTV is more permanent than gasket gaskets shrink over time.