i believe i read before that the 943's were not interchangeble cause the caps were stuck and 933 your could scew of the caps. mine you can screw of.
well, they do sell caps for the "slimlines." I can't be certain which model SP has in stock, so I don't know what they are calling slimlines. However, if you can screw off the caps, then it looks like you can screw on the adapter and use the cheaper AT853 caps. Again, I would call AT or SP and confirm my nonsense.