Ive used Iodine, it doesn't make beer bitter, boiling hops at the begining of the boil makes bitter beer, so does using bitter orange peel, Iodine... never as far as im concerned, after I am done with my star san I am going back to Iodine. I dont like the foam starsan produces. everyone says dont fear the foam, well I let the foam sit over night once and in the morning there was a large puddle of water/starsan I dont want that in my beer, Iodine foams, but not as bad.
Just a thought, but if you boiled a gallon of water in a boil pot and just set the bottle in the pot with a lid for 15 seconds 220 degree water with full surface contact should sterilize 50 bottles in no time, Use tongs to roll around.
If your boil pot has a faucet you could fill each bottle with boiling water and reintroduce the water back into the pot x 50 and you got sterile bottles. Dangerous yes, but there you go, nothing in this hobby is non dangerous. Use gloves and protective gear!
experiment and let us know what your findings are.