In answer to your question, I've had decent luck trolling with a 45 degree angle or slightly less but I've only been salmon fishing a couple years so my experience base isn't big enough to rely on very much.

The reason I fish Silver Horde's slower is the wisdom passed down through my wife's family (I'm from Kansas) who were taught by a real "old man of the sea" who fished Mission Bar and Tulalip before there was a bubble. As the stories go, he was the master, and no one could get their boats to go as slow as he could but he caught more fish.

More recently, I've been taking advice from Salmon University and cranking up my trolling motor (especially for silvers) and having good luck.