Alright, I'll try to simplify the situation as much as possible. You're fishing a brand new hole, you have never seen this place before but you know there's a pile of silvers laying on the bottom. You get your gear out, pop open the fly box, which fly do you choose?
To simplify the situation more, this hole is 4-6 ft deep and the water isn't moving terribly fast. But good enough for a decent drift. I'll let you guys figure out the color/clarity of the water based on the most common water for your area.
Me, Most water I'm fishing is brown muskeg water. First fly is usually a chartruese clouser during the early season. Purple ESL later.