Personally I don't think I would feel comfortable using any kind of paint from the hardware store. Mostly because I do not have enough information regarding this. My cages are all powder coated and I wouldn't be sure if the paint would affect the coating that is already there. Luckily I don't have any birds that are chewers but many birds do chew on their cages and I would be afraid of the bird digesting paint chips. If stainless steel cages werent so astronomically expensive that would be the answer to every bird owner's problems!
As far as the smell of paint still being too strong, it could be that it is too humid and is not drying as fast. Also check to see if it is adhering well to the metal. You may find that you need a primer first which will put you through a whole other dilema of finding a safe primer.