try blades from Harbor Freight. Inexpensive and change the blade when it gets dull. Also pick up one of the books on Rotary Cutting - look at the library. They usually discuss issues such as those you have If you have a LQS, check to see if they have a class on rotary cutting. There is a skil to it which a class might help.
And in my opinion the electric sharpeners don't work as advertised.