You can't miss "The Sinks". Info sign and a parking area at it. Be really careful around that pool. Its really deep and has a nasty current. Not mention is steep on both sides of it.
Not sure if I'm understanding your post right. To get to there you would need to drive back toward Townsend/Cade's Cove from Metcalf. Not sure exactly how far it is but it will be on your left. Can't miss it.
This is a picture I took of "The Sinks" standing above the falls at the parking area.
Not much room to fish the big pool from the sides but you might be able to get below it and fish back up.