I have a 7' M spinning rod I use for spinners 1/4 or less. Is 8 pound line to low for that ?

No

Only if you aren't getting a solid hook set with it. 

Thanks for the help. I will let ya know how it worked

8 should be fine for something like that. 

Sounds good to me

Last year while on a trip to the boundary waters CA, I found myself using only spinner baits (except mr. twisters for the eye's). Since the only rod I had brought was a medium-medium with 8 pound mono on it I got to know this set up pretty well. After that trip I wouldn't recommend using mono for spinner baits at all, maybe it you had like 20+ pound or something to the point where it stretches only a small amount, but I wouldn't recommend that. I also have a rod Med. Med. with 8 pound braid that I feel is a little weak for spinner-baits IMO. In recap, after the trip I spooled 20# power pro and haven't had a single complaint yet. I think you would be fine with 8 pound mono, floro, and braid, it's just IMO there are better options out there.

Sure. As long as you are in pretty open water.

I use 10 - 12 pound  test and cast them fine with my Curado and a 7' M BPS Crankin' Stick.

I have a 7' M spinning rod I use for spinners 1/4 or less. Is 8 pound line to low for that ?

 

Currently the majority of my spinning reels are spooled with 8# mono.  Many years ago I fished with 4# mono a lot casting small Beetle Spins and Roostertails.  Back then bass were a bonus.  Most of the fish caught with those lures were calicos, rock bass, perch, bluegills and sunnies.  No problem with the fine wire hooks penetrating.  My PB smallmouth was caught trolling a small inline spinner (Roostertail) on a spinning rod with 8# mono while I rowed the boat from one fishing spot to another.  Ignorance was bliss.