With the materials available today, it isn't that difficult to tie a large fly, 6 to 10 inches that won't wear your arm out. Just need to do a bit of pre planning. Figure on tying it out artificial materials, that don't absorb water or shed it quickly. Take a look outside of "fly fishing" hooks. There are several brands of straight shanked light wire worm hooks that are size 1/0, 2/0 or larger that are strong and not nearly as heavy as the equivalent salt water fly hook that would be using for a large fly.