Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
If you purchase Pliger rubber or Serilor rubber you will not have any issues with swelling. Also what are you cleaning them with?
One other thing we did back in the day before it was easier to get the right size rubber, we would use some ink degradent as a lubricant and it would help slide the rubber in much easier.... That statement is LOADED with plenty of opportunity for jokes. 13 hr day, and I got nothing.