Balloon rigs can be a great way to fish under the right conditions. I mostly use balloon rigs in eddie areas where I want the bait to drift around and cover the entire eddie area or to anchor above snags or holes and allow the current to silently drift the rig right in front of a snag or hole with out splashing a 3+oz weight and a big ol' bluegill or Bullhead (my choice bait) right on top of the fish and spooking them off or to get it right over the snag suspended above the cover to keep from snagging.
I use them as a slip rig with 2-3 ounce weight and hand sized bluegills or bullheads but you can fish any bait you want on a balloon rig. You can fish a smaller weight with cut baits but a 2-3 ounce lead holds a live hand sized Bluegill straight down under the balloon fairly well which is what you want. The way I rig them allows me to remove the balloon and fish on the bottom or attach the balloon and fish suspended without having to re-rig my poles every time.
I use and recommend balloon rigs for certain conditions or techniques for several reasons:
#1 reason- I can unclip the balloon and fish on the bottom in a matter of seconds without having to retie all my rigs, sometimes I might move from holes where I fish balloons to holes where I fish bottom 4-5 times in a night and with slip bobbers I have to retie each time, with the balloons I simply unclip the balloon and Im fishing on the bottom.
#2 reason- variety of colors, mostly at night I use white balloons but if they are generating water below the dam it creates all the white foam that floats on top and makes it difficult to keep up with a white balloon so I may switch to yellow or if fishing multiple rods in daylight we use different colors on each rod so if we yell out bite on red or bite on yellow we know which rod to go to instantly.
#3 reason- I work at a Ford dealership and we use heavy skinned balloons by the handfuls to tie on to the cars and signs and all and they are free to me !!
The way I rig a balloon rig is to first tie on a bobber stop ( I use Thill brand bought pre-tied in packs of 5 at Wal mart), then thread the line thru a large bead with a hole not much bigger than your fishing line.. very important so the bobber stop tie doesnt pull thru the hole in the bead but the line passes thru easily. Then feed the line thru the eyelet side of a very small snap swivel. Then tie on a large barrel swivel on the end. On the other end of the barrel swivel I tie the leader line of anywhere from 6-24" depending on conditions then I usually tie on a circle hook.
To adjust the rig you slide the stop knot up your line to the depth you want the bait suspended.. Say 12' deep in 15' of water for example. When you cast out and it hits the water let it free spool allowing the line to start sliding down thru the small swivel eye and the bead above it. When the stop knot comes off the reel and hits the bead it stops passing thru the bead and pulls the bead down to the swivel (which has the balloon clipped to it thru the thick rim part of where you blow the balloon up. So now the balloon is on the surface and 12' of line has passed thru the swivel and is stopped by the stop knot hitting the bead and not being able to pass thru it and the bead hitting the swivel and not being able to pass thru it. I hope that makes sense to ya. I've attached a few pics to help visualize it.
For night fishing you can add chem lights inside the balloons before blowing them up and they will show up pretty well in the dark.. ofcourse a clear or white balloon works best for this.
One more tip- on windy days to keep the wind from blowing your balloon rig around so much fill the balloon with some water before blowing it up, it puts weight on the bottom of the balloon acting as a ballast the same way your buoy markers do and helps steady it in the water more.
Good luck.... Sam