What line should I be using for throwing spinner baits? Spinning reel/ MH rod with a 1/2 oz to 3/8 oz double willow spinner bait.

Imo ...14 pound to 20 pound mono depending on cover and water clarity. It allows for a little stretch and I think that makes a difference sometimes in not pulling the bait out of their mouth and I prefer a medium heavy baitcaster... Rod Length.. vary from a five and a half foot pistol grip to a 7 Foot depending on cover and particular bait... again.. in my opinion.

Your spinning reel is only going to like the lighter line and there lies the problem. Breaking off is not a option for me; so I am not going light line. I would test out the braids on it; so you have heaver poundage with smaller diameter. See if you can get by with 30#. If not go down to 20#; but that would be it for me.

I've been using McCoy's Mean Green with my spinnerbaits this year and have been very happy with it. It's a little more expensive up front but it lasts a long time.

But don't overthink it. Plenty of pros made a lot of money on Stren or Trilene monofilament before other line types became popular. Go as light as you are comfortable with, especially if you are just fishing for fun. 10 or 12lb Big Game is cheap, just most like spinnerbaits!

12# big game.

I throw 10 to 12 lb. mono, for lighter spinner baits... just my preference, as I think braid tells me too much. 1/2 oz. I do 15 to 17lb. braid. I know i'm strange! I use a bait caster for spinner baits.

Those Big Bass like the 1/2oz. Spinner bait. IMO

12pd big game!

Spinning reel, I would throw 12lb. mono (anything heavier will coil up on you pretty bad) or 30lb. braid with optional leader.

Baitcaster, I like to throw 14-17 Suffix Mono. Doubles as my buzz bait and walker,popper rod.

I guess I am the exception. I thrown them on braid and it's always worked well for me.