If you are thinking of using a solution feeder, you probably won't like it long. Most folks don't because they take a lot of baby sitting. They also take up a lot floor space if you sue the proper size retention tank.
If you're planning on a solution feeder, I'd suggest an inline erosion pellet chlorinator with a special mixing tank that is equivalent to a 120 gal retention tank.
If you have the chlorination set up properly all the iron, IRB and H2S etc. will be oxidized and then removed with the carbon filter IF it is sized and set up correctly. Otherwise you'll foul the carbon, it will fail and then the softener will see dirty water and soluble iron and it will fail.
IIRC it is said that you need 4 ppm chlorine per ppm of iron, but don't depend on that, I hate feeders and haven't set one up for many years. You also need a minimum of 20 minutes retention before the oxidation is complete. Meaning that the water is in contact with the chlorine for at least 20 minutes before the water exits the first fixture.
Quality Water Associates