I want to fish large beetlespins for bream in river with my bait caster. I have a 8:0:1 on a 6' medium light rod. New to bait caster this year but love it and dont want to go back to spinner reels. Fishing out of 1 man boat so went with shorter rod for this setup. I know very little about line so any advice would be appreciated. Thanks!

How much do those large nettle spins weigh? If they’re at least 1/4oz, any good bc reel worth its weight should be capable of tossing it. 
 

As for the line, I don’t have experience here, but I would use the lightest line I can get away with given the environment I’m facing. If mono or fluoro, I’d start with 8-10# test and make any necessary adjustments. 
 

One thing to keep in mind if you have to make long casts into a strong wind. They’re akin to spinnerbaits and as a result, a spinnerbait’s less than stellar aerodynamics at times will need a vigilant thumb. The wind can slow the lure’s progress just enough to cause a little bird nest or overrun if you don’t use your thumb to compensate. 
 

Last thing, reels are tools. Both reels can handle many applications quite well. However one type might excel where the other might be lacking. 
 

Therefore, it is my humble opinion that it behooves bass anglers have both at the ready as opposed to using only one type. There have been many a time where I was in situations where I brought only one type or the reel I needed to use was out of commission— and boy, I wish I had the other because of the conditions.  Even if you have 10 bc reels to 1 spinning reel, you’re covered, lol ??

I have 1 bc setup for that kind of fishing.  I’ve tried several lines and have found that Yozuri hybrid 6# test works very well for me.  It handles 3/32 Neds and heavier.  I couldn’t go that light even with 8# mono.

How To Cast Light Lures with a Baitcaster

 

 

https://www.bassresource.com/bass-fishing-videos/how-to-cast-light-lures.html?fbclid=IwAR2LGZ44cmkn9DzANsm_MlVDJ1D1uD2qbueG9dcjW9iHl_7e9HrMNofrnX8

The thing that helps most casting light lures is keeping loaded spool mass and inertia down.  

For deep spools, I back halfway with 20-lb mono (20-25 yds) and top with my thinner working line.  

no problem casting 1/8 oz on this reel. 

A beetlespin to target bream is a little small to cast well on most traditional baitcasters.  I suggest you give it a try anyway.  It will give you a feel for the advantages and disadvantages of bait casters and spinning reels.  A lesson learned in the field is worth far more than one read on the internet.  Bream fishing definitely calls for finesse tackle which means a spinning reel or a bait finesse system (BFS) baitcaster.  Also check the weight of your lure and make sure it’s within the suggested lure weight range printed on your rod.

 

As for line,  I’d recommend a $5 spool of 0.009 diameter monofilament like 6 pound Berkley XL.

A beetle spin is pretty light, but if I remember correctly its normally a 1/16 lead head, plus plastic, plus the wire and blade.  I bet you're around 3/16 all in.  With a medium light rod you should be able to get there.  You want something soft and flexible to come off the reel with minimal effort.  10 lb 832 braid is on my comparable rod and is a good choice.  For bream and moving baits I wouldn't even use a leader.  6 lb mono like a trilene XL or sunline supernatural would be worth a try also.  Neither is expensive to try.

I cast 1/4 ounce lures with a baitcaster, my Abu Black Max combo, using 10 # Big Game line. If I remember correctly, I have specifically used the 1/4 ounce Beetle Spin.

 

The rod being graphite makes it harder, a fiberglass rod loads differently and works much better. I sometimes also use a cheap zebco fiberglass rod, since I don't have a decent quality glass rod. That combo, usually accompanies me when I'm bank fishing creek banks with plenty of cover, partly because of the casting qualities of glass, partly because it's shorter and easier to handle in cover.

 

I digress, if you use a 1/4 ounce Beetle, and you use a reel you're familiar and comfortable with, I think you can do it just fine.

6# YoZuri hybrid. Very smooth casting, but surprisingly strong. Landed a large catfish on it today when walleye fishing. It did great.