Scott,
I think there are a few things to consider here. Not only line type, but also rod type if you are looking at sensitivity and feel. I would first look at your rod if you are looking for sensitivity and feel and then look at your line selection.
I usually use a 1/4 to 1/2 OZ. slip weight on Mille Lacs for pulling live bait rigs, depending on wind and wave action. I do not pull spinners a lot (as of yet), so I’m not sure what to say there.
For live bait rigging, I usually use 8lb Firleine Smoke above the swivel and 4 lb (Smoke or Flame Green)for the snell. This gives me great sensitivity and feel on my 7′ ML action Fenwick HMX. I fish with a couple of buddies that I often outfish live bait rigging. Many days, the bites I get are really light and more of a increase in weight on my rod tip. I’m guessing that my buddies are also getting bit especially after they switch to my snell set up, but just are not feeling the light subtles bites and misssing fish catching opportunities. They usually fish with a cheaper rod in a medium action shorter 6’6″ length spooled with the same Firleine. I have fished with my Fenwick for the last 4 to 5 years. I truly believe the more you use the same rod and reel set up the more you will understand what each different vibration means. So find a set up you like and stick with it.
I am also searching for even greater sensitivity and looking to purchase my first St. Croix Rod this Spring. Either a Avid or Tournament Legend 7′ to 7.5′ ML Rod. I also fish with Shimano Symetre and the next style down???? reels. Along with line type, the rod and reel are just as important if not more.
This is what has worked for me and just my $.02 worth. Hope it helps.