I have outdoor windows that were placed on an addition by the previous owners, they weren't very smart.

the outside sill is made up pieces of wood that let rain get into the wall...so now I am fixing that rot

instead of just using glaze to hold in the window, i want to use a piece of wood to hold the window in and to cover the gaps on the sill. But i still want to use something for the wood to sit in and help waterproof....which would last longer?? Setting the wood on a bead of caulk, silicone or glaze??