Well met PL. I believe you are correct with the wedding choice of tweed and trews. You may even go without the waistcoat for that event, unless you are a member of the ceremony (in my opinion).

I like a bit more "spit and shine" for a Black-tie gala, so I would consider an Argyll or PC jacket (cost prohibitive) for the other functions. There are things my wife knows about the "social environment" and apparel needs that I rely on. Most that have long marriages listen to those small, but potent, voices (as I try to do).