Check to see if the ribs were packaged in a brining solution. If so, they already had the salt added, which could lead to your increased salty flavor. If they came in a package similar to the one below, then they were most definitely presalted. Presealed packages tend to have the solution. If possible, try to get ribs that look fresh and arent vacuum sealed.
The great thing about the charcoals are that they burn at a slow, fairly constant rate. When I was charcoal smoking, I'd add a piece or two every so often like you mentioned. As long as you dont forget about it and let your temps drop too low, you should be fine just adding a piece here or there. The problem comes when it drops too low, and you have to start another chimney to get enough coals going to bring it back up.