I think that castability is the priority here.

Remember that for most spinning/casting tackle, a four inch bait or lure is considered a 'finesse' bait. Most bass plugs are three to five inches long, soft plastics are in the four to eight inch range, a spinnerbait is usually around five inches long and about three inches high.

Few of my bass flies approach those sizes.

I've caught ten inch bass on twelve inch plastic worms, and had three little six to eight inch fish hit the same 5 inch minnow bait (actually landed all three).

It's unlikely that we can fish with a fly that is too big for ANY reasonable sized bass.

I catch most of my bass on subsurface flies that run in the two to three inch lengths. Usually leech or crawfish patterns. I try to keep Clousers at five inches or so, but decent length bucktail is getting harder and harder to find.

I use long tails on my topwater largemouth flies, looking for four to five inches. Sometimes I can't get there with the materials I'm using.

I can cast most of these with six weight rods, which are my usual choice for bass. I try not to have to use heavier gear, but for some presentations, you need a nine weight and bigger flies.

Buddy