As others have indicated, Ryanair are very strict on the luggage now. If one case is 16kgs and the other 14kgs, you will have to swap things round. I've lost count of the number of people who end up with their suitcases open on the floor in front of the check in desks moving items around!!
Although I've not seen any hand luggage being weighed, when I flew with Ryanair last week, no-one was allowed through the gate until all of their hand luggage had been combined into 1 piece. The fact that this took most of the bags over the hand luggage size didn't seem to matter, however, I suspect that will be the next thing they clamp down on as they can make money forcing people to check these over-sized bags in.
Personally I've never had any problems with Ryanair - if you follow all the guidelines to the letter then you should be fine.