I tie a wooly bugger type fly. Use a size 4 or 6 hook, weighted with lead wrap and a bead head so it'll get down fast. I only tie white and yellow and use estaz wrap. Essentially, it looks like a lead head jig.

At the falls I drop it where falling water hits flat water and let it drift a few feet then strip it in.

An 8 wt. will be good. I use a 7 and can't turn bigger ones when they hit the current. I get broke off/cut off a lot. The smaller ones come in pretty quick but the bigger ones are like tieing on to a car.