2 piece ears are difficult because of the flexing as said.
With that being said I would never, never, never use a silicone sealant on any joint that was flexible and difficult to seal with a gasket. What happens when you flex the joint and break the elastic bond/adhesion between components, under pressure?

My advise to the OP is modify the ears to be one or buy a one piece plate coupled with some quality gaskets. Make life easy.